[iCeCuBEz v2]

FF 7:
Cloud - Default character and omnislash did quite a large amount of damage. Only thing annoying about him was that his power got really weak as his HP depleted.
Barret - The largest damage dealer compared to everyone else and his Limit Break was pretty powerful.
Cid - idk, at this point I pretty much have anyone, the last time I played this game I think I had cid. He's another large damage dealer and his Limit break is alright.
(Essentially the only thing that really mattered at the end of the game for me were the ultimate weapon effects of the players and their Limit Breaks. I would grind for hours inside the Crashed Gelinka, and got it to the point where all these characters had all stats at 255.)

FF 8:
Squall - Lion Heart was really powerful but the chances of actually getting it as a final blow were pretty small.
Irvine - AP ammo deals a massive amount of damage, he's very useful.
Quistis - She was very good for leveling up, because you could just keep her at low health, go to Island closet to hell or heaven or w/e, and just have her use degenerator which is a one hit kill. Having this makes leveling up incredibly easy, and I just got everyone to 100 in like a day.

FF 9:
Zidane - Default character
Steiner+Vivi - If you had steiner you kind of had to have Vivi alongside him. Steiner's physical attacks dealt a lot of damage, and Vivi's black magic was very powerful.
Eiko - She had very useful restorative magic and Holy was a pretty powerful spell.

FF 10: Since every one of my characters had 255 stats, it didn't matter who I used. The only thing that differentiates these characters at this point is their overdrives. so....
Tidus - blitz ace
Wakka - attack reels
Yuna - I just used her because she could summon, and summons were cool.
ps. Anyone who picked Auron lmfao his overdrive is atrocious.

FF 11: I forget who I used, I'm still playing it haha. I think I had Ashe, Basch, and Vaan.

Also since the Final Fantasy games are generally easy, it really doesn't matter who you use haha.