Is it possible to have dinner at Rose & Crown, watch Illuminations and return to the Contemporary to watch Wishes from your room?
I doubt it, but it will ultimately depend on what time Wishes shows on the night in question. IllumiNations almost always starts at 9:00 and runs for about 15 min. If Wishes is at 10:00, that only gives you 45 min to clear the park wait for a bus (or get to your car), make the drive (park if you drove) and get back up to your room. Could it be done? Maybe, but it will not be easy, and if relying on buses I would say very unlikely. If Wishes is at 11:00, you should have no problem.
An alternative would be to valet park at BC or BW when you arrive in the AM. Watch IllumiNations somewhere around FR or UK (the bridge is a very good spot) exit out the IG, make the easy walk to BC/BW and drive back to the CR. This will still be tight, but more likely to work out for you than trying to get out the FW exit.