Charles Xavier:
Boy: Edward Erik Xavier
Girl: Kaira Hope Xavier

Erik Lehnsherr:
Boy: Christopher Charles Lehnsherr
Girl: Kate Astrid Lehnsherr

Hank McCoy: 
Boy: Thomas Samuel McCoy
Girl: Emmalie Sky McCoy

Alex Summers:
Boy: Luke Nicholas Summers
Girl: Lauren Isabella Summers

Peter Maximoff:
Boy: Percy William Maximoff
Girl: Nova Primrose Maximoff
(A/N: A lot of people don't like this name ^ but I personally love it. What do you think?)