Field team:
Cyclops
Storm
Colossus
Nightcrawler
Wolverine
Kitty Pryde (new recruit)
Support:
Professor X
Jean Grey
Beast
The original X-Men besides Scott have kind of moved on to other things but make apearances.
Introduce Rogue in the 2nd movie.
Oh and cast most of the characters in their mid to late 20s. Kitty is late teens