Fran Bow is pretty underrated and it's safe to say a lot of creators don't know about it. It's also risky to put a lot of time into something only a small amount of people would get. That's why mods of very popular games/books/movies or original creations tend to do better than mods of obscure games/books/movies.
That would take a very long time, and certain characters would take insanely long to make.
You would need to figure out how to make the realms and how to make them function.
That is pretty much impossible on most mainstream mod-creation apps.
You would have to be a very skilled creator (or possibly a team of them) to make a project that large.
If it was an open world thing, it wouldn't take as long. However, something like that would probably follow a story, which would take even longer to make.
I know I'm late, but I hope this helped