I like the uncommon hero approach.
Also agree with the suggestions Bats and tickle made. Special attack is very cool.
Was thinking it would be nice to have a subtle tie in with Emma Frost. The best thing I can think of is requiring one of their powers to need clear sight and then Emma will have that Telepathic Link power that omael suggested that would give them all clear sight.
One other thing, their stats seem really good for 80 points. Might lower them to attack 3 and defense 4. Would be nice if they were a little weaker than Emma or Jean Grey individually, but when they team up they can do some damage with that special.