If there was one Claremont story I'd want to see adapted, it's the Demon Bear Saga.

Magik, Mirage, and Cannonball are the absolute must-haves. With Magik there's a question of how they handle the supernatural element. I can't see them calling it New Mutants and not being mostly Claremont's characters. Otherwise 'Generation X' or 'New X-Men' would make more sense.