At the Movies!

[GameWizard001]

^The Sinister Six reference is towards the end

Spoiler

in the prison scene with Harry/Green Goblin. It is brief but it is there. I am bummed that they won't have all the Marvel characters apart of the MCU and that Fox is creating its own Marvel universe. Because they are shooting themselves in the foot just because so many of the characters cross other characters paths so much that you really can't go too far with either universe. Spiderman in some iterations even crosses paths with SHIELD and Nick Fury along with the Avengers.

As to Quicksilver and Scarlet Witch, they are gonna be in both at one point. The reason they can do that is that both characters were at one time Avengers but also apart of the X-Men universe so it is a weird loophole. However the MCU movies can't make references to them being mutants as anything related to that is strictly within the X-Men comics. But they can make them Meta-humans. Humans who just so happen to have special powers for "reasons."

I know, it is stupid and should just be one or the other but it is one of those weird copyright scenarios where both can have their cake and eat it but no whip cream, that requires a different sort of contractual agreement on both parties part which would require someone to have a cherry and the other with out and could instead accept a strawberry substitute.