I'd say Mark Hamill works better with Marluxia, but using his voice as Fire Lord Ozai from Avatar, while Dante Basco (Zuko in Avatar) works for Zexion. As for Larxene, Ashley Tisdale works. Vexen, since he and Hojo fo FFVII share the same seiyuu and are both mad scientists, i'd go with Paul Eiding. Lastly, Lexaeus, since he's a discipline brute, needs a deep, manly but sophisticated voice. Methinks Ron Perlman will do the trick.
