Re: Patrick Stewart & Ian McKellen Return for Days of Future Past
I'm guessing that Stewart will be able to feature, because someone from the future (maybe Cable?) will come back to the time of the original trilogy but before the events of the Last Stand. That would be the easiest way round it without having to explain how Stewart's Prof X is still alive. Not everyone is going to remember what happened in X3 with that aftercredits scene.
Then maybe there will be scenes that happen during that period, and some that happen during the First Class period. I doubt though that Stewart and Mckellan will be the ones to time travel to the 60s and meet McAvoy and Fassbender.
I don't see any problem with Rebecca Romijn returning though. She did a cameo in FC.
But how about Kelsey Grammer?
Anne Hathaway: "You did not just ask me that!! What a forward young man you are!!! My goodness!!"