Most of the other matches seem pretty well covered, but as an extra two cents...
Yuki (G3) vs. Vincent Valentine (FF7) - Vincent actually strikes me as the type who'd spoil Yuki, normally, what with his 255% accuracy weapons. Flash is very very good evasion, yes, but it's not entirely perfect - Yuki can be hit while he's attacking, recovering, dodging some other attack, etc. Yes, Flash gets considerably better in a duel, but it'd feel weird to have Flash that fully obscene - it's similar to spells that focus against one target but normally are used against multiple targets. Plus, even with Flash unleashed, Vincent is from a game with complete wait control - theoretically Vincent can wait to watch Yuki's attack animation start, then quickly hammer "Fight." Weird things in general happen with thinking too much about wait abuse, but the general point is that if anything can hit through Flash, it'd be Vincent's guns. 255 accuracy is an entirely ridiculous amount - it pretty much asks to be comboed with Deathblow Materia in game for free double damage, and I don't recall ever really missing even on the Deathblows.
That said. Just because Vincent could spoil.... I don't think his stats are good enough to actually do so here. Even though he's going to be in the backrow which does help his defense a good deal, Dragon Slash will still be enough to break through. Even if Vincent does get a Limit off... then he DOES have to deal with Flash's awesome evade, since I don't think his transformed moves necessarily ignore evade, though I forget. Plus, I'm generally inclined to be nice to Yuki in other ways, what with him having the most skill slots in the game, even if deciding which skills are legal can be a headache. Don't even think he really needs them here, though.
