I think two parks is an absolute last resort scenario, but they could be reaching that point. The big question in my mind is if they might want to expand the guest areas to surround the soundstages and shoehorn another house and a scare zone back there. If not, then two parks might be the only option.
As for Shrek, I think if they came up with an exciting, profitable concept for that location, HHN wouldn't stop them.