Planing a return

[C-Dude]

Hmm... okay, I'll give it a go and give you a thorough plot outline of how I imagine a Thamasa/Vector split would play out.  I like the principles PowerPanda applied in ThreeScenarios: each branch should have approximately the same length, should round out at three playable characters in the party, and should give each character an opportunity for growth in the story (Sabin and Edgar trying to piece their brotherhood together after estrangement, Terra and Banon forced to see things from the other's perspective, and Shadow demonstrating his skills as an assassin and alluding to his fears of authority).

For me to achieve the same result with a Thamasa re-pathing, I need to first inform you of my character interpretations/reimaginings.  Rather, it's how I read and rewrote Terra, Celes, and Shadow.  These could be considered spoilers for ReCast, so I'll put them in spoiler brackets.

Terra
[spoiler]

I wrote an expanded backstory for Terra Branford, which she recounts at the top of the Zozo building after the party returns from the Magitek Research facility.  Having been taken by Gestahl, she was handed off as a toddler to Doctor Cid Branford (yeah, I know his canon name is Marseilles or something, this worked better).  He raised her in captivity in one of the magic-draining tubes, which he perfected with her input.  She was eager to impress him because he was the only person she ever got to interact with and his praise was the only positive feedback she ever received.  He basically raised her like an attack dog (that's why she can use every weapon type in the game... at least in my hack).  When she learned what the research was actually being used for, she set out to burn it and anything that had come from it.  She got 54 suits, troops included, before she was subdued and slave-crowned.
Augmentation was also perfected based on Cid's examination of Terra.  For this reason, Celes is younger than Terra.
The takeaway is that Terra is a biological weapon, and afraid she can't be anything else.  She's less a robotic 'what is love?' character and more a tormented 'will I ever be more than a weapon?' character.

[/spoiler]

Celes
[spoiler]

I didn't buy the helpless damsel role that the game tried to cast on Celes.  She's an imperial general, not some love-starved twit!  More importantly, we know that she's applied ruthless tactics in the name of the Gesthalian Empire.  I recast her as a cold masochist, partly as an explanation for how Runic works and partly as a means of expressing the contrast between Kefka (the devil on her shoulder) and Leo (same spot, but the angel).  It also makes a better parallel to the Warring Triad, with Celes filling the role of Poltergeist.
Why a masochist?  Well, I imagine that when struck with a spell, Celes still feels the pain, even though her blade absorbs the magic as energy to refuel her.  As a coping mechanism for this, she taught herself not to feel anything at all.  She was also raised in captivity by Doctor Cid Branford, and the guy was a weapons developer... he's more about making tools than rearing functional human beings.  I can't go into more detail about this without spoiling another character from ReCast (and a very moving deathbed confession), but let's just say Cid's had lots of tries and he hasn't gotten one right.
Recall that Celes torched Maranda?  Cyan reveals this in Narshe when everyone meets after the first split.  This will be of particular importance.

[/spoiler]

Shadow
[spoiler]

I use Clyde Arrowny instead of 'the Shadow' in my hack (he thought Baram's idea was corny.  He's also more sympathetic than the train robber of the original game; he's been sending money to Thamasa in secret from all of his jobs, to Strago, for the purpose of taking care of the village and his daughter.  This arrangement is a secret, so when Strago sees Clyde and alludes to it there are harsh glares to be had.
Shadow has a long talk with Terra about his daughter on the boat ride to Thamasa, dovetailing the exchange with Strago later.  This interpretation REQUIRES Clyde be present to save his daughter from the burning house, but also requires he seek out the rampaging espers to protect her from their destruction.  Hence, he is included in both branches.

[/spoiler]
====

I was thinking about it and the best place to set up a three-party split is right after Relm spills the beans about the Village of the Magi.  To get everyone that needs to be there in the right position to make this work, we have to adjust the intro to Thamasa.

Party: Leo, Terra, Shadow (Locke and Celes in tow, unplayable)
Rather than having Leo and Celes storm off, all five characters and their Vector entourage enter Thamasa together and request an audience with Mayor Gungho (whose house is changed to the biggest house in the town.)

New Asset: Big Thamasa House (map), Unburnt
Recreate the general floorplan with the Towns Interior tiles.  Have several chests, some locked, some not.  When one party returns to the burning house later, all locked chests are unlocked and all previously unlocked chests are empty (Siegfried stole them if you didn't get them in time!  ...Hmm... come to think of it, why didn't they use Siegfried in Narshe instead of Lone Wolf? Oh, I'm getting distracted)

Celes gives Gungho a gift from Emperor Gestahl as a sign of the entourage's good intentions.  Strago enters to talk to Gungho (triggering his naming sequence), but is startled by Shadow's presence and thanks him for the last payment.  Shadow glares and leaves.  Both Strago and Gungho deny the existence of magic.  Leo expresses the importance of finding the Espers, but to deaf ears.  Instead, Strago asks for details about the gift.  Celes glances at Locke and leaves abruptly.  Locke chases after her.  Leo and Terra decide that there's something suspicious going on and set out to investigate the village (and see all the little scenes of magic).  They can talk to people about this, but the only one who'll spill the beans is Relm.  Shadow comes in with Celes and Locke, who are still arguing (or rather, Locke is pleading and Celes is cold-shouldering him).
When Strago denies Relm's claims, Celes casts an ice spell at him, which he deflects.  With no other option, he reveals the secret of Thamasa [the scene that usually happens after the fire].  Strago agrees to escort Leo and Terra to the holy ground in the mountains, while Celes and Locke stay in Thamasa to keep an eye on the Magi (and the Imperial troops).
This is where the split begins, cut to the black screen and pick a scenario, kupo!

Locke, Celes, Relm
At the Thamasa Inn, Locke continues to plead with Celes to talk to him.  She asks why he thinks she's a good person, he knows nothing about her.  He doesn't have an answer.  Then Celes explains how she took Maranda: she set the village on fire and promised to put it out with her magic only when they had surrendered unconditionally.
Then there's a loud rumble.  The package Celes gave to Gungho had exploded [yep, it's a Cecil reference ], setting off Thamasa's supply of enchanted weapons.  Relm runs into the inn begging for help; her friend lives in that house and he's still inside.  Relm runs out and starts fighting the fire, to the harsh wrath of Gungho who proclaims magic is forbidden (they don't know that the imperials already know).  Celes joins in to try to extinguish the flames, declaring this will not be another Maranda.  The villagers join in too, but the inferno is too intense; Celes volunteers to go in and find the survivors, with Relm insisting she go too.  Celes declines the offer, but Locke points out the girl clearly has magic too (works better if Relm learns spells by leveling) and could be useful.  The three charge into the house, playing out the burning building scenario as it would have in Vanilla, with the exception that the unconscious child behind Flame Eater is the little pyromaniac boy (still works, smoke inhalation wipes the party and Shadow still shows up to rescue Relm... and the others simply because they're there).

No sketch tutorial here; Relm will briefly explain how she wants to capture the life of the flames in her paintings, with the players working out its utility through experimentation.  Note, I generally change the sketch results to be more useful given the situation (casting ice against fire monsters, etc.)

Terra, Leo, Strago
Strago leads Terra and General Leo into the Crescent Mountains to search for the Espers holy ground, where they erected their monument to the Warring Triad.  No major changes here, except the Ultros Battle doesn't have a sketch tutorial in it: instead Shadow joins the party and helps push past the struggle with his Throw special (well, for me it would be Payday, he bribes Ultros to leave, but I recommend still converting it to a real boss fight).
When the espers approach threateningly, Leo and Shadow protect Strago (instead of the vanilla staging, Locke and Strago protecting Relm).  The events are otherwise identical.

Edgar, Sabin, Cyan
I'm... not ready to plot out this branch yet.  Unlike the other two, it'd have to be from scratch, be relatively short (15-20 minutes of playtime ending in a boss fight), and explain how the rest of the Returners escaped Gestahl's vector trap.  I _do_ know that it involves the Tea lady, at least!  Perhaps Cid too.
But probably not these three.
We should collaborate on this one.
Rough Idea: everybody is taking tea in the Imperial Palace barracks. Right as Edgar is about to take a sip, Cyan stops him and notes that the drink looks odd. Recognizing it as the same poison that was used at Doma, Cyan slaps the cup aside and grabs the tea girl, demanding an explanation. Edgar insists that approach is too harsh for a lady, and instead sits the tea girl down for a chat. Turns out Leo was sent on the goodwill mission to get all the Leo loyalists out of the city, so that Gestahl could let Kefka out. They're going to execute the Returners, capture the Espers, and then use that power to force the door to the Realm of Phantom Beasts and fetch the Triad.
Sabin sends Gau (and Mog if present) away to warn Setzer and get the Airship, since they can climb down from the palace safely. Then Edgar suggests they might be able to escape themselves by climbing down the broken cranes from Kefka's previous air assault. They fight their way past magitek soldiers and IAF pilots to the top of the palace.
...Seems too short, though, and I can't think of a good boss fight. Kefka would be anticlimactic because he'd just have to run away. Gestahl might be interesting (being he's a VERY powerful magician), though he honestly might be too powerful for these three to wound him (and thereby win their escape).

[Catone]

With a first read, I get the feeling I'll want to pull back in some aspects (closer to vanilla) and go farther with other aspects. While this plan defiantly fills several story holes, it almost (again this is after a quick read) feels to far away from original for my own goal. Least I think, will defiantly be re-reading everything later, slower.

Something I do see the potential for, sort of, is at least one "battle ground" type battle, (like with the mogs) either in Vector as as escape battle, or in the burning building (as a defensive type battle, reach the victim then defend against advancing fire). Or both for that matter, most of those battles are done through lots of event code, and based on what I had already started writing (least, as best I can read it) I could almost reuse some code between multiple battle grounds.

You see, something I wanted to do with those was set up "officers", prior to the main boss, who until taken out would continually send troops toward the team. Forcing the player to either charge quickly or risk being overrun and eventually just wore down from a never ending battle. While the Vector escape could use some filling out with a battle such as that, the burning building just seems perfect for that type of battle.

Thinking about it, some changes will defiantly have to be made to characters, from vanilla, just because the vanilla story is so lacking and well, some stories just can't be filled out the way they are in vanilla. Again however, I do want to try and not rewrite what is there as much as practical.

Eh, that's the point of brain storming though, all I've got time for at the moment anyway. And still have to get started relearning coding as well. Once things settle down enough for me to dive in, I should, probably, maybe, remember some coding skills. Getting time to start again is the limit at the moment.

[Lockirby2]

Nice to see you back Catone. Good luck with the hack.

[C-Dude]

With a first read, I get the feeling I'll want to pull back in some aspects (closer to vanilla) and go farther with other aspects. While this plan defiantly fills several story holes, it almost (again this is after a quick read) feels to far away from original for my own goal. Least I think, will defiantly be re-reading everything later, slower.

Could you tell me what's bothering you about the proposal?

My take on Celes isn't as far afield as it seems: she's canonically responsible for ending Maranda's resistance with fire.  It's the action that brought Doma--Maranda's primary shipping and trade partner--into the war.  Thamasa is the perfect opportunity to address this history, as well as wrinkle her relationship with Locke (who hates the empire for applying a similar tactic in Kohlingen, a move which ended Rachel's life).

If you don't like my take on Shadow, it lifts out like hydrogen peroxide pulls out a stain; Shadow and Strago needn't interact at all.  Apparently the developers originally intended to have Strago confront Shadow in a scene which was later cut.  This makes it a good point for vanill-ish expansion.  However, it all depends on how much you want to explore the characters: like you said, you're not going to be able to expand the game's story without putting some chocolate syrup into that vanilla.  Granted, you don't have to go as far as say writing Locke out entirely in favor of Cid as a playable character, or depicting Umaro as a time-traveling robot disguised as a sasquatch because his chronograph told him the wrong year and he thought he'd have to blend with cavemen , but you have the right to take liberties where characters are undefined.

With all that in mind, I understand you want to stay as close to the intended narrative as possible.  For a Thamasa split, the only character I could see as being truly problematic while kept vanilla is Terra.  If she remains a lovesick robot and she gets alone time with Leo in the Crescent Mountains, it takes the sting out of his subsequent murder in Thamasa (barring a significant rewrite, including the loss of the haunting statement "I wanted to learn so much from you"; such a rewrite being the very thing you want to avoid).  Keep in mind vanilla Terra has no characterization beyond her amnesia and her obsession with love: even after her reunion with her father's crystal corpse she doesn't fill in the details between toddling child and Arvis's removal of the slave crown.  To write new content for her at all she requires motivation beyond her amnesia persona, and motivation comes from backstory.  And being worried about being nothing more than a living weapon isn't that far of a stretch, I guess the only deviance my version makes from established canon is the motivation behind burning the troops.  According to the guide that discussed it, Kefka made her do it as a test of the Slave Crown, which... honestly doesn't make sense to me, why would Gesthal allow him to massacre his own soldiers?  That's poor asset management is what that is.  Especially with his forces hitting a wall in Doma.  Dude, you don't start a new front with a currently submissive monarchy AND throw away soldiers on some experiment when you can test the experiment in combat against your currently hostile foes!

...

Alternatively, if the thing that's bothering you is Relm entering the burning building instead of Strago, I'm not sure how that could be remedied.  Without making her playable at the start of the burning house scenario, she gets no growth opportunities before the Floating Continent.  Keeping the entirety of Thamasa's story vanilla, though, makes the branch too long in proportion to the Vector escape, and leaves no room for two of the characters.  If that were the case, you'd probably want to handle the Vector escape as a flashback, starting after Edgar's arrival in Thamasa but before Kefka's attack.

You see, something I wanted to do with those was set up "officers", prior to the main boss, who until taken out would continually send troops toward the team. Forcing the player to either charge quickly or risk being overrun and eventually just wore down from a never ending battle. While the Vector escape could use some filling out with a battle such as that, the burning building just seems perfect for that type of battle.

Ooh, that'd be perfect for the Vector escape!  Move the scene from the barracks to the Vector Bar (a woefully underused map, if I do say so myself), then do the battlefield in the city proper (possibly with new boxes/unbeatable encounters as well, to constrict the player's mobility).  You have to get all three parties to stand at the top of the palace stairs to end the fight.
I'm having a little more trouble picturing it in the burning house (I get that spawning flames would infinitely spew bombs at the player, but the win condition escapes me).

After reading your idea, I also had some thoughts about setting up a similar encounter in the Crescent Mountain statue room (goal being get to and beat Ultros, perhaps even multiple times around the room), but coming up with minions for him to launch at you (except maybe extra tentacles?) proved too difficult for me, especially given the confined space of that room.  It doesn't help that I feel Ultros too is a terribly under-explored character--his origins a mystery and his purpose nothing more than a running gag.  Considering his first appearance on the Lete River as the Returners base was under attack, I like to think of him as a failed Augmentation experiment (too much magic injected, turned him into an Esper, just as anyone who stepped between the Triad's beams would be) trying to get back into the Emperor's favor by attacking the Returners' back door (the birth of a rivalry).  With that interpretation, he could easily send wave after wave of monstrous aberrations or magitek machinery at the players.  Without it... he has Chupon.  Which is a thing I suppose.

Anyway, just think of all of this blathering as food for thought.  You don't need to use all or even any of it.