No Fantastic Four because Marvel doesn't own the film rights and can't cross promote them. I'll give you Asian Hulk as a variation, but I really don't know that much about that. As for female Thor, teen girl Iron Man, and the multiple Captain Americas, I would argue that those characters are being used to setup casting changes in the films for when the long used actors don't renew contracts. Easy to slide the new version with a totally new cast right in to replace them.
Same as above, but it already happened. X-23 is the new movie Wolverine....