Restricted Cast, who would you pick?

I doubt I could get it down to 4 characters but I can definitely eliminate a few.

I'll edit this post as I come up with ideas, and make this a containment area for my criticisms of FF6, FF JRPGs, and SE in general.

Most good JRPGs have either a good execution of a bad cliched JRPG plot, or a bad execution of an interesting plot. FF6 is a bit of both, but leans toward the former with some very big lapses here and there. If I had submitted it to a writing class, I would fail the class.

My understanding of story and plot is that you write interesting and coherent characters, put them in a world that is logically consistent (not necessarily real world logic), and let them bounce off each other. You could say it's the lazy way of writing a good story, but it works.

Character 1

Realm, Mog, and Gau use different variations of the same mechanic - Strago too, to a degree. I'd roll them into a Saga Frontier type monster, which can change forms, gains stat boosts exclusively from absorbing skills from defeated monsters post-battle, and has it's own unique weapons and armors. Instead of Magic it would get Blue Magic, and it's 3rd skill slot would let you choose (with accurate descriptions) one of the monster skills it's learned. Monster skills wouldn't require MP and would use any stat for their effect, while Blue Magic would cost MP and use the Magic stat for their effects as appropriate (so Self-Destruct wouldn't use Magic at all except maybe for accuracy, since it uses HP for damge).

Non-Blue Magic monster skills would get a 1 turn cooldown so you can't spam them, have a table with cooldown numbers for each skill, or have the cooldown rely on the skill power byte(s) for duration.

A shape-shifting monster can make for an interesting story, depending on if it has human intelligence and how long it lives. Could be a sort of demi-god or nature spirit, or a human cursed to live forever without a static form. If the latter, what that human(?) did to earn that curse and what s/he was beforehand is a great source of characterization.

There are a lot of myths and stories about mortals earning curses from various eldritch beings. The shapeshifter could have been basically the Beast from Beauty and the Beast, he could be a man who dumped his wife for a newer bride, he could have stolen something from a temple. S/he could have been someone who wished to change his/her gender or appearance and asked the in-game equivalent of TES Daedric Prince Clavicus Vile for this, and didn't read the fine print before s/he signed on the dotted line - getting EXACTLY what s/he wished for, to his/her chagrin.

That still leaves the issue of why an immortal shapeshifter would care about a temporal human empire, or the concerns of normal humans.

I really like David Bowie, so maybe I'd just make the shapeshifter David Bowie. Put them on a starship and have them crash land on the planet, and have the party recruit them as a hidden character after some long sidequest. They joins up to get parts to fix their spaceship, be a tourist, and see what the humans are up to. This meshes well with the gender implications of a shapeshifter too, and lets you play with the implications of a character that can literally transcend gender and species in a world where everyone else is stuck with what they were born as, something which may be of interest to the furry and trans audience.

Character 2

Sabin, Umaro, and Shadow could become one character, a non-mage barbarian monk who throws stuff. I'd put the Blitzes in a menu and give them a cool down after use proportional to their power, effect, and number of targets. This is to prevent you from always using them instead of Fight. Throw would remain the same, maybe allow multi-targeting for shurikens and the like but reduce the damage or make it consume more items. I'd give him a limited vocabulary and make him huge, brutally strong, very fast, kinda dumb, and easily angered. Maybe make him a her and produce lots of snu-snu jokes too. Source material for the character would be the white-haired, blue-eyed, deathly pale northern barbarians from the Robert E. Howard Conan the Barbarian universe, where civilizations rise and fall over and over again; people devolve to ape-men and then re-evolve back to human over time; and tectonic plate shifts and the planet rolling around on it's axis radically changes the climate every few 10,000 years.

Maybe add some Raymond Feist Dragon Lord or demi-human themes themes too. Or make him a pure "I see things, I smash them, I get paid, I carouse, I get arrested, I pay fine, I need money, I take job to smash things to get paid." This would make him/her a good contrast to the Terra character below, and maybe a consort of the same since he/her is both easily manipulated via base impulses but also totally immune to complicated deceptions that require higher thought processes.

Maybe steal the Grendel and Ginger Witch character from Beowulf & Grendel, and have them be Grug Sabin's mom and dad. Have her run away from or driven from her community due to her magical abilities, she meets basically slightly more humanoid (or not, if you play it for laughs) Umaro, and settle down on Umaro's mountain top to raise kids and herd mountain goats. A passing Shaolin Monk is impressed with the size, strength, and ferocity of 9 year old Grug Sabin, and persuades Grendel Umaro and Ginger Witch to send Grug Sabin to Monk's monastery to study martial arts and ki magic and whatnot.

Character 3

Cyan, Celes, and Leo would be rolled into a Samurai + Dark Knight + Paladin + Sword Mage semi-mage character. Sword Tech would be selectable from a menu and then heat up to execution, to prevent it from being a better option than Fight. Runic would become a Sword Tech, and would behave much more intelligently (affect only enemy and charmed/hostile ally spells, persist until used, number of Runic instances would be a byte instead of a bit flag so you can stack it to block multiple spells from hostiles). I'd make the Sword Techs reminiscent of the aforementioned classes, and steal ideas from the Brave New World mod. Instead of getting more powerful skills that make the previous ones obsolete, new skills he learns would give him more options.

Instead of Magic this character would get Sword Magic, purely offensive spells that combine a sword strike and a spell. No heat up or cool down, just an MP cost.

Swordsman - or swordswoman - could be any combination of those characters in terms of characterization. Maybe make him or her a powerful tool and enforcer of the empire, who is of course betrayed and has a crisis due to the betrayal. Maybe they think it's all a misunderstanding and continue to drag Terra/Circe to the empire, only for his/her former comrades in the army to obey the emperor/magistrates/whoever and beat him/her senseless.

I'd play this character as the Straight Man, but give him (or her) the option to occasionally belt one of the pranksters with the flat of a sword to turn the tables.

Character 4

I'd mix Setzer and Locke together. The Steal command would become a Theft skill set, where you select two utility skills from a small menu of 6 to 8 skills. These skills would be very minor, hence why you pick two at a time instead of one. Steal would go here, as would Morph if I keep it (a deathblow for enemies in critical HP, with a HP or MP cost to the caster, that grants an item if successful). Skills to view enemy status, stealable/morphable items, and generally do housekeeping things that don't fit in any other skillset and aren't that useful to merit a spell all fit here.

The Slots command would work as that one hack to it on this site does, where each roll gives you a 30% chance to get that effect and the last 10% is Lagomorph (minor HP and MP heal). I'd add the option to reroll your end-result once, and you have to take the rerolled end-result no matter what.

I'd also put a timer on the slots, so you have like 5 seconds each to pick an option for each of the 3 slots. Not sure if I'm explaining this correctly.

Setzer-Locke could basically be a combination of the two personality-wise, a gambler, escape artist, and heister who graduated from common theivery. Alternately, make him a courtly highwayman and pirate, who steals as many hearts as he does valuables.

He always runs away when the party gets captured and steals their belongings when he finds it convenient, but he always breaks them out of jail.

Maybe give him X-Item to round him out, or give that to Edgar. It probably goes better on Edgar.

You could also play with the character in different ways by making him older and more cynical and lazy, like John Dortmunder in the aforementioned Donald Westlake comedic heist stories. Characters don't have to be 17 year old combat veterans, he can be in his mid 30s.

The Slots skill give you an opportunity for characterization. You could lampshade the game mechanic with a flashback to a time he robbed or broke the heart of a powerful sorceress, and she cursed him to have to make decisions at random. He found a way to use that by getting very good at rolling dice, playing darts, and playing slots/cards as a way to gain an advantage in combat. This demonstrates his slippery, canny nature and explains why the heck some guy is throwing dice in a sword fight.

Character 5

I think that leaves Terra. She would be a pure mage, and her morph command would give her 1/2 current MP costs (stacks with anything that affects MP costs), make all her spells mandatory multi-targetable if they aren't already, remove any penalties to multi-target, and replace her magic command with double cast. She'd also get the Summon command to replace Revert while morphed. When not morphed she's pretty much the same as vanilla, only with mage-only gear.

Right now I'm feeling the most interesting characterization for her is deceptive predator, who feigns weakness and poses as bait to get people in range of her charm and command spells/traps. Think Circe in the Oddesey. Maybe our party is tasked with capturing her, highjinks ensue when they fail at first, later they win and put her in a cart and ride back to collect the bounty, only for a corrupt magistrate to attempt to imprison them and steal the reward/glory for himself. They are sentenced to death as her accomplices, and since they're going to die anyways they decide to break out and lead a rebellion against a corrupt, unresponsive, and calcified empire.

I'd leave it in the air if all of this is our Circe-Terra manipulating the magistrate, our party, and people in general as payback, and to become the beloved queen of a new nation. It would be funny if a self-serving character does good things totally in spite of herself. I prefer anti-heroes who are forced by circumstances outside their control to do good, and how they feel about, react to, and use this to further their own goals or otherwise change and grow.

Did I forget anyone?

Character 6
Oh yeah, Edgar.

Lancer/Dragoon + Engineer/Mechanic. Not a lot you can do with Edgar. Maybe just rebalance his Tools and replace Magic with Jump. Jump can coexist with Fight if they're used in different circumstances - Jump when you want to deal damage and avoid it, Fight when you want to stick around to tank for the softies a bit. Jump could also benefit from different behavior with different types of weapons, or with specific weapons. You could have a weapon (or weapon type) that turns Jump into a hit-all, and another that makes it hit twice or three or four times; and have both reduce the damage to 1/2 to balance things out. Other weapons or weapon types could increase the debuff/spell/crit proc rate for Jump.

I'd rebalance the tools such that none of them are worth replacing with Fight, at least not always. This would involve making them all either elemental, or forcing them to inflict a status effect before dealing damage and having the damage fail if the effect isn't inflicted.  Add some healing and buffing options. I'd give each individual tool a significant cooldown as well, so you can't spam the best in each circumstance until you win.

Give him X-item and make plenty of useful items, but none that are excessively powerful at any level or with any stat/gear/skill loadout.

For Edgar as a character I'd make him a madman happy to tinker in isolation. Maybe make him out to be a demon or vampire to the party, which turns out to be rumors from superstitious bandits who attempted to raid his mechanized fortress of solitude. Hype it up to be some big battle with an uber-boss, but have a hidden option to ask him nicely to join you and he will - anticlimactically - say "okay, sure" after asking if he'll find interesting machines. Still have the option to fight him to force him to join you, but make him rather grumpy about this for the rest of the game.

He's a good candidate for another hidden character.

You could have some fun party dynamics by making him immune to Terra/Circe's charms by making him not care about people in the slightest. Now that I think about it, everyone in the party should have some degree of immunity to her wiles, because it would be funny. The shapeshifter because s/he's not human, an inherently magical creature, not definitely gendered, or already cursed and thus immune to further curses. The Cyan-Celes-Leo hybrid could be immune to charms due to harsh training, willpower, special effects bestowed on elite imperial warriors, or because s/he's just that rigid about sticking to his/her personal code. Locke-Setzer would be immune to her charms due to his vast experience and know-how of seducing women to steal everything they and their families/husbands own, and generally being somewhat sociopathic in that regard. Having random NPCs come up to her and propose marriage would be funny too, especially if she gets so frustrated by it that she literally sets them on fire or strikes them with lighting bolts as she gets tired of dealing with it.

The plot/story would have a lot of elements stolen from Donald E. Westlake comedic heist books.