The edits you made to add cast members to officially-announced movies like The Boss Baby 2 were removed because DreamWorks has not announced yet who will be in the movies. Until they do, edits like yours are fan fiction. But because you didn't say it was fan fiction and it was added to an official DW project, technically it's false information, which is a form of lying. Don't try to "help" by filling in information like this with what you make. Wait until it's officially announced.
As you found out on the Disney Wiki, some wikis crack down hard on fan fiction what isn't identified as fan fiction. If you want to write your own DreamWorks stories, go over to the DreamWorks Fan Fiction Wiki. At the very least, put something like "this is my idea for who will be in the movie" in the Edit Summary. It will probably be removed, but at least people will know you're not deliberately lying and trying to commit vandalism by putting it in.