I could see it happening. When the news HMH wasn't taking place this year I was honestly surprised, because with IT Chapter 2 (sequel to one of the highest grossing horror films ever) coming out Sept 6 I was wondering why WB wouldn't want to capitalize on that by having an IT haunt for synergy. This could be their solution to that since they aren't able to hold the event this year, while also maximizing profit from licensing and merchandising. If the teams already had a pitch for last year, then Murdy and Mike's tweets about a last minute massive house pitch that was hugely successful, with little prep time and with someone Murdy grew up being a fan of, for an IP nobody thought they'd do....it would all makes sense if it ends up being IT. This year's synergy house, or another thought, they got the original film like the Halloween 4-Halloween 2018 situation of last year and there's this year's classic maze. With Chucky being more the synergy maze if true.
I could be way off, just adding to the speculation lol.