I think the problem with that is whether Rowlands would ever agree to it. She was pretty hands on with every facet of the Universal projects for the parks. Her one non-negotiable requirement was that no character impersonators for the main characters be in any of the parks. Which is another reason why I don't think it would have worked with Disney.
Agreed. Jo Rowling is VERY picky when it comes to who she allows to touch her work and how much. Which definitely isn't a bad thing, since it's helped the brand keep a solid reputation over the years. It would definitely be the kind of work she'd have to be super involved in.