Is there insider knowledge of Conjuring definitely not happening? The Nun comes out right before the event, it seems like they would have had enough time to secure the rights for a Conjuring Universe style house which is kind of like a "best of" for the series. They could save IT for next year with Chapter 2 coming out on Sept 6th, which would be a big get showcasing both films. And I'm not convinced that Halloween isn't happening. It's a Blumhouse film and the first Halloween film distributed by Universal. Given the relationship they've had with Blumhouse at the event, the massive appeal of the property, and the fact that this is now a Universal film it'd be quite a missed opportunity to not feature it.
Just some food for thought.