Gonna put it out there that I think the only attractions I think are truly in danger are MIB, FFL, and T2. MIB and T2 would definitely get a pretty big reaction if they were to close soon, and while FFL wouldn't; I could see a lot of people being upset if Bill and Ted's venue got closed at the last minute forcing them to not show up this year. Since this is about a pre-Nintendo USF project, it definitely won't be E.T. since if that closed it would be for Nintendo, and Mummy still is incredibly high-rated and marketable making me think it's safe for a little while longer.
My personal theory? That FFL is going to permanently close on September 4th, and because of this short notice for HHN ops, it means that Bill and Ted is not happening this year and the future of the show will be unclear. Then Uni is gonna try to get the Forbidden Forest and Ministry of Magic attractions to open on the exact same day in 2019, to draw over people visiting for Star Wars Land.