Just stay true to what the characters look like in the comics. The X-Men are so diverse anyway.
Bear with me for a moment... I don't think this is actually true.
Of the X-Men, not counting characters, like, say Angel Salvadore who have been X-Men in comics but are considered "taking someone's spot" when they're included on a team, we have
White Males: Havok, Iceman, Beast, Scott, Xavier, Wolverine, Banshee, Colossus, Nightcrawler, Sabertooth, Gambit, Longshot, Angel, Cable, Magneto
White Females: Polaris, Dazzler, Jean Grey, Rogue, Psylocke technically, Marrow
Black Males: Bishop
Black Females: Storm, Cecelia Reyes
Hispanic Males: ...
Hispanic Females: Cecelia Reyes
Asian Males: Sunfire
Asian Females: Psylocke-ish
Other Males: Forge (First Nations)
Other Females: ...
And that's before we even get into quality of inclusion. For instance, take a look at the classic X-Men storyarcs and villains, and how many of them emotionally spotlight white males versus females, to say nothing of minorities.
Contrast this with, say... GotG: Two white guys, the original ambiguously biracial man, a pacific islander and an afrolatina. In fact, every film except for the Avengers films has been much more diverse than this, and even with those, they keep getting more diverse each time. Is X-Men ready to be that diverse? Not going by their past rosters...
Now X-Men gets a lot of credit for diversity by headlining Storm so well, and by including a lot of non-racial diversity, thematically and otherwise, but when it comes to racial diversity, they actually haven't moved since the 80s while everyone else has caught up and, in some cases, passed them.
Marvel Studios across film and TV, has a habit of gender and race swapping characters, but only the supporting ones and not the lead characters.
True. Question for all:
How many of the X-Men are lead characters?
---
Honestly, I think part of the appeal to use the diverse members of the X-Men's extensive roster is lipservice. In my experience, when we get a diverse team of C-listers, like in First Class, people complain that it's not the "real" X-Men, not the "real Angel." I think when we ask to let the B and C-list X-Men be the diverse members of the cast, some part of us assumes that they will remain B and C list as normal, and not take the places, narratively, of our A-list White X-Men. If the possibility of "Brown Beast or no Beast at all" was presented, I think the spread on what people would prefer would be much different.