September is still pretty hot. So Splash definitely would soak up some people, figuratively and literally. The waits for Splash can be decent, so factor at least an hour's worth of standby time there, that won't be in the queue. GMR is a longer ride, so it soaks up some as well. Mission Space hasn't been all that hot of a ride really, HoP? I think they're waiting on Trump to see if anything happens, so as to not have to refurb it again sooner, lol. Ellen never really has a wait.
ETA: There's another thread going right now that if you had FP+'s booked for GMR, that you were apparently given an anytime FP if your dates were between Aug. 13 and some time in November... Talk about a random score there...