Sorry, but I still don't see problem as resolved or explained. We can't have The Avengers with Iron Man, right? This is the same situation.

It was said before that it was fine to stay as it is a Godzilla sequel. I don't know that I agree with the comparison.

That's honestly fine with me but I'd like to know what should I do when there's a movie crossover between two (or more, for example three) characters. Should I add it to collection of character who plays bigger role in the movie (like with Frankenstein Meets Wolf Man)? But if both characters play as big role, should I add the movie to Character A Collection because he had a movie before Character B? Sorry for maybe confusing wording but I just don't know what to do in such situations. Example: Kamen Rider × Kamen Rider W & Decade: Movie War 2010. The movie consist of three parts: Part 1 is completely about Kamen Rider W, Part 2 is about Kamen Rider Decade and Part 3 is a crossover between them. Both characters play as big role in the movie, so should I add it to Kamen Rider Decade Collection, because the character had movies before this one, unlike Kamen Rider W, who didn't have any? Or should I add the movie to Kamen Rider W Collection who was the star of his own TV series at the moment, where he originated from, so somehow he can be considered more important? The movie also continues character arcs from the TV series. I'm very sorry for spending your time with that but I'd like to know.