Out Of My Vulcan Mind wrote:
Essentially, if it's mentioned or seen in a FOX-produced Marvel film, FOX holds the rights to it from there on out (which is one of the reasons there were so many fucking worthless and pointless cameos in The Last Stand and X-Men Origins).
Those characters are part of the package of rights whether they appear in cameos or not. The producers include the cameos because they think fans get a kick out of them.
Yes and no. I believe that there's a codicil in the contracts about if the characters aren't used in 'x' number of years the rights revert back to Marvel.
At least that's the way it was back when Roger Corman made his FF movie. It was never intended for release. It was just so the studio could retain the screen rights.
Nor sure if the X-men movies are like that, but they might be.