Crystal Ball gazing for 2019.
I think Disney will be running a lot of specials before Star Wars opens up next year, after that I think all the Orlando parks will see a boost because of it -- particularly the Magic Your Way fl resident promotion. After SWGE opens, forget it. Although the AP blackout dates and timing of AP price increases this fall will be telling for WDW. They may do special things for Epcot above and beyond that since that's going to see the largest attendance hit by far next year.
Universal will do better early on because of the new HP Coaster (new T2:3D replacement show will also help), and will see rising tide benefits from Star Wars when it opens (So will Sea World). If Star Wars opens in October of next year, HHN will be stupid crowded.