Well, we can set Apocalypse as the X-men reason to be gathered and maybe the first enemy.
Like I said before, do OC at a fresh start game is like to say "I don't care with X-men ideas and concept" IHMO. It is the perfect moment to take a name or a concept and revamp it perfectly. Who said Angel must be the winged mutant? Or Rogue should be a girl?
Now here is an essential question. Are we going to be in a special school, live under a special house and attend a normal school, or we can jump to, let's say, everybody is a freshman at the some l"community" college?