Hollywood Horror and Make-Up Show is a long show and inside.
Jimmy Fallon is a long, interactive queue experience that you can take extra time going through (if you want) -- inside. Expect the 'ride' (including the queue 'experience' to be at least 40 minutes). ET's queue is really long and inside/cool. You can take you're time walking through it. The ride itself is longer too, though not really conducive to slouching and closing your eyes. You're on a 'bike'.
Sinbad and Animal Actors are longer shows, seated and shaded but not indoors. Posiedon Fury is indoors and an extended show but you're moving along through it and standing. Since you're there at the holidays, I'm assuming, the Grinch show will be running. Also longer, inside and sitting. Though, it's a good show so you might not want to close your eyes through it.
There's the American Express lounge, if you have that and bought your tickets with it.
I'm blanking on the name of the stage -- but there's a big park-like, grassed space in front of a stage by RRR. Lots of people spread out there. There's also benches around "Central Park" on the USO side.
There's lots of little quiet, sitting and shaded spots here and there. If Discovery Centre is still open it's indoors and cool, though not exactly quiet. But you can spend as much time there as you want.
If you do just need to chill out, you can always go out into CityWalk and go into a bar/lounge or restaurant for a couple hours. If you really want to chill out and sit there's the movie theatre so you could go and catch a show in the afternoon.
Or you could take one of the boats over to the various hotels on the resort property and zone out in the lobbies, lounges/bars, by the pool, in the arcade, etc. Cabana Bay has a bowling alley. The pool bars and the rum lounge at Sapphire Falls are nice. Lots of memorabilia at Hard Rock to browse, etc. There's walking paths to all the hotels too that are scenic and quiet to just get out of the crowds for a bit. But the boat rides are only about 5-15 minutes depending on which hotel you want to go rest/chill at.