Vayne and Cid Raines I may understand... Gilgamesh is already in. Dark Knight is a general term and Cecil can already do that. Seifer isn't really unique either. Just give Squall Seifer's trench coat. But yeah, villains from I-II-III... notably Astos & Xande... IV, Zemus/Zeromus... X... Yunalesca? I don't want Seymour and we apparently aren't going to see Shuyin... I don't know the villains of XI...

Characters I still cross my fingers for...
Yang or Edge, Faris, Shadow, Genesis from CC7, maybe a Turks, maybe a Tsviet, I wanted Zell, Fujin, Kiros, Beatrix, Blanc (as a costume for Zidane?), Gilgamesh from 9 (a costume), Necron, Brother, Shuyin, Leblanc (has she appeared as a guide?), Paine, Gippal, Balthier (naturally), Fran... heh... lol yeah... I'm picky...