I haven't seen anything lately on the "MGM name is leaving" front. That surfaces every once in awhile because the agreement between Disney and MGM doesn't allow Disney to use the MGM name in certain marketing materials. So, people see the planning video that calls the park Disney Studios and the rumor starts again. In fact, when they show the park's sign in the video, MGM is even removed from the picture.
The rumor about the Mann theatre is that since Disney owns the competing El Capitan theater across the street from the real Mann, they don't want to promote the Mann in their park. Hence the BAH is put up, blocking the view.
We're going in May, so that's too bad for us if the GMR is going to be closed. Hunchback is already closed, so I guess we won't be spending quite as much time at MGM.