One question here would be that how derivative works are handled? Like let's use some character as an example. They appear in movie with other characters. Would

One question here would be that how derivative works are handled? Like let's use some character as an example. They appear in movie with other characters. Would you need to pay for each character and movie separately? If movie gets bought out would that allow making other works based on characters in the movie? Also, would licenses terminate when copyright gets bought out?