Battlescript variables...

questions to your answers incoming:

1) From my notes, the MMMMMagic cutscene is controlled by bit 1 (0x02) of $3EBC / $1DD1. I don't think it has anything 
to do with $3EB9. $3EB9 is different. The "X" is the bit index. Check out the code at C2/30E8-C2/310D for more details.
"Battle index" is just the battle number. I think FF3usME calls it the "Formation" Index.

From M-tek armor battlescript:

Code:

[script #-1]   ; orig idx=66, "M-TekArmor", nb. bytes=24
F0 EF EF B5    ; Rand. spell: Special or Special or Tek Laser
FF             ; End first wave of attack
FC 14 0C 01    ; If VAR012 has all the following bit set: 1
FC 01 02 02    ; If monster has been attacked by cmd: Magic or Magic, will target attacker
FC 15 09 01    ; If VAR009 has all the following bit cleared: 1
F9 00 09 01    ; VAR009 toggle bit: 1
F7 06          ; Trigger event: Terra + Edgar + Locke (about Terra's magic power)
FF             ; End

M-tek armor deals with var 009, bit 1(3EB9) as well, i read somewhere that even bit 0 had something to do with it, 
but i can't remember exactly where, in the case.
in any case in your RAM you consider both 3EB9 and 3EBA as a single variable that is composed from 2 bytes...
about Sr.Behemoth:

Code:

[script #-1]   ; orig idx=281, "SrBehemoth", nb. bytes=194
FC 08 36 05    ; If target self is affected by status Imp
F1 44          ; Targeting: random ally
EE             ; Battle
EE             ; Battle
FD             ; Wait until the attack sequence is called upon again, then continue (reset targeting)
.
.
.
FC 12 01 00    ; If following monster is/are dead: #1
F9 01 0A 00    ; VAR010 set bit: 0
F5 0B 03 00    ; Monsters  are hidden and their HP restored, diagonal
F3 7C 00       ; Text: " Enemy's coming from behind!<D>"
FA 06 00 00    ; Allies switch from right to left side
F3 7D 00       ; Text: " Another monster appeared!<D>"
F2 00 A8 81    ; Call form. #424 (SrBehemoth), gets max HP
F9 01 00 00    ; VAR000 set bit: 0
FE             ; End If and reset targeting
.
.

i'm pretty sure that for changing formation "call form. #424"(already used this command elsewhere), is more than
enough, so i wonder how the code at C2/30E8-C2/310D is called during the battle...
besides those 2 var's values don't look like any formation number involved, probably they tell which element the 
program has to check in "Formations to Change From" list(yet i don't know where 3EB9 comes in play)

considering all what i said above, the only thing that M-tek armor and Sr.Behemoth have in common is that they both
call a battle event(not exactly, Sr.Behemoth calls an FA command instead) and since i don't get where C2/30E8 is 
called, i'm starting to think that it's called inside the event/FA command itself.
I remember that there are certain battle commands that can be called only in some specific battle formation like
final battle against kefka that makes scroll BG vertically; they also told me that FA command that makes move the party
on the left side of the screen can be used only in Sr.Behemoth formation, otherwise the game will glitch... could 
that depend on var 3EB9-3EBA and the matching formation? 
Understanding how this thing actually works is very difficult but it would be a great discovery! if we collaborate 
here, we might find the answer. 

2) The emperor's banquet thing is a little weird, and I think I remember that it doesn't really work correctly. 
I think it's supposed to work like this: After a battle with one of the soldiers, the screen is supposed to 
flash a different color depending on the outcome of the battle. Red if you died, blue if you ran out of time, 
green if you ran away. I didn't test this, but you can take a look at the event script at CC/886C for an example.

I saw the code, yeah it works in the way you said, but it's actually not a matter, as far those battle variable bits
values are changed according to the outcome of the battle: even if they are used before the banquet, they can still be
used anywhere. 

3) Yes, the monster variable is stored separately from the other variables. $3ED4 is the battle index and is not 
accessible as a battle variable. Also, the program sets bit 7 of the monster variable when a monster uses seize. 
This is hardcoded into the code for seize. If you look at the AI script for the tentacle battle, it checks bit 7 of 
the monster variable to determine if a character has been seized.

well, this is a nice discovery! i didn't knew there was a way to know if seize was used in battle! just saying...
if i set bit 7 manually even if i never use Seize, it's not like it might happen something weird, right?