Don't count on that.It's very unlikely Bryan Singer does anything to reference The Last Stand.We are left with 2 possible choices here. 1:It will be Xavier's mind In Trin Brother's body but never referenced as such on screen. Cyclops and Jean may not but In film Inless they cameo at film's end after the time traveler returns to fuutre to find changes. 2:They outright Ignore the events of Last Stand. Right now It appears they are going for 1.Bryan Is not going to spend a lot of time dealing with the disaster Brett Ratner did.He's going to spend time on DOFP story.