Mr. Fantastic-George clooney (a little old i know but i really like him for the role) or maybe colin hanks so theres less of an age difference between him and sue
Invisible woman-Rachel McAdam
human torch-Brett Harrison
The Thing-really liked the earlier suggestion of james gandolfini (perhaps in a mocap suit)
Doctor Doom- kenneth braungh (voice only, i feel doom should sound very theatrical, almost Shakespearean.)
directed by Duncan Jones or robert zemeckis ( good with mocap, not the whole movie, just for the Thing and any aliens that could be featured) or if you like practical make up, i think maybe frank oz, good rapport with the hennson creature co., good at ballancing drama and comedy (of course i've only ever seen little shop as a sample of his work, but i loved it)
score- Alan Silevrestri