Don't know who the original team will be (but I doubt it will be the orginal 5) Wolverine, Cyclops, Jean, Storm and then fill in the blank probably. But to the original question I absolutely believe Marvel would be open to other groups of mutants (x-factor, x-force etc.) if the opportunity presents itself.

There's also the chance that they go with a couple stalwarts (wolverine/cyclops), and then start combing all the various x books to fill out the team for something different.