Re: Jennifer Lawrence/Mystique. Introducing this sexy and talented actress.
How about cameo-ing others characters through Mystique.
For instance, say there's a scene where Mystique has to change into some random people.
Maybe she can change into some mutants that us fans will recognise.
It gives us a chance to see someone who may not appear in a film.
There's no need for characterisation for them and it establishes that these people exist, bcos shes got to have met them.