Here are my ideas for the trilogy if it is one
X-Men First Class
-The X-Men is Professor X, Cyclops, Marvel Girl, Beast, Storm, White Queen, and Banshee. Forge should have a cameo. If Shadow King is the villain the two Psylocke twins will play a x-men 1 rogue type role.
-If Arcade is the villain Quicksilver,Toad,and the Psylockes will join him in an Amusement Park and fight the X-Men.
-Juggernaut would be a secondary who decides to kill Xavier, the X3 stuff can be cleard up when the kids work together to remove his helment and Prof.X erases his memory of him, so that he will not come after him again.
X-Men First Class 2
-Stryker could return with Sentinels who kidnap mutants for him. Mr.Sinister could help Stryker experiment with on the mutants. Gambit could appear and save Lorna Dane/little Polaris or they could both be kidnapped. Alex Summers/Havok should be kidnapped also and him and Lorna should meet and show intrest in each other. Gambit should team up with the X-Men to stop Stryker and the Sentinels. The Mauraders could be run by Stryker and Sinister.
X-Men First Class 3
-Magneto runs the Hellfire Club with Scarlet Witch and Quicksilver with him. The original hellfire club could be there also Sebastian,Selene and friends. The X-Men fight against all of them and Emma could betray the X-Men and join the club being fed up with Xavier not letting her use her full potential and Jean taking Scott's eye off her and Xavier's attention as one of his fav. students. Dazzler could sing at the club as a cameo. Magneto could meet Mystique here.