Re: Jennifer Lawrence/Mystique. Introducing this sexy and talented actress.
My two cents.
This is a prequel to the first three movies, right?
Ok. In these movies Xavier and Magneto was old friends but it's clear that Mystique was "sort of in love" with Erik.
Mystique says also that he has "left" her "human form" when he joined the Magneto's part, after Erik and Charles have broken their friendship.
She says also that "Raven Darkholme" is her "slave's name", so this means she has taken Magneto's side.
it's clear that, in Singer's vision, Xavier and Magneto and Mystique are all old friends in past.
Well i presume that Mystique has a Wolverine-like mutation, so she's more old than what appears.
The 10% of scene in blue's skin are justify. Xavier teach to all his mutants to never use their powers. If you see the trilogy the X-Men never used their powers when they're nearly to humans. They use their powers only if necessary. Remember, right?
So I presume that Raven, that is a friend of Charles, never use her powers in public. But when she embrace Magneto's part she's understand that she has to "transform" into Mystique. All the time.