Those are gray-area dates where the summer hours and events are reving up, but you might miss something. Known rehabs are the Great Movie Ride in MGM and Pooh in Magic Kingdom (both of which make me sad, I'm going June 6-12). You'll miss the opening of Mission Space by a couple months. Other than that, there don't seem to be any scheduled rehabs.
My big question on those dates is the COP and Timekeeper, both in the Magic Kingdom. They are seasonal attractions, and I'm thinking it may be close to the end of May before we know their status.
But beyond those things, you should miss nothing!
Pat