I would pick
Arly Jover as Emma Frost, she played Deacon Frost's blonde girlfriend in Blade, so she's used to doing stunts and was quite sinister, which I think fits Emma.
Edward Furlong as Gambit, he might be kind of short, but he's a great actor, with longish messy hair that reminds me of Gambit a little bit, and a smaller skinny frame which I think would be more akin to Gambit as the agile thief.