It bears noting that X-men in media have never used the O5 to start. The first X-men three movies didn't start with them, The first class reboot didn't use them. None of the cartoons began with them. I think Wolverine and X-men is only thing that has O5 together useable if they wanted. I don't see Marvel movies breaking that trend but if mutants are just being found in the world like new phenomena then O5 would be pretty good choice but I think they would extend roster by 2 or 3. So it would be like a Original 7 with Storm and some other minority character maybe Forge or Psylocke.