I wonder if we could get an Annabelle or Nun house before a Conjuring house. I don't know exactly what the IP holdup is with getting The Conjuring to this event, but maybe a deal could be worked out for the spinoffs and pave the way for the main series.
Two other possibilities I could see next year are horror films coming out over the next two months: It, mother!, and Happy Death Day. HDD looks easy enough to translate into a house (Hollywood supposedly has it in their Blumhouse) and Universal has the rights to it, but the former two have big ifs associated with them. We know Stephen King hates lending his stories to horror events, but Warner Brothers just set up a limited time promo haunt for the movie in Los Angeles that is drawing huge crowds. Maybe King has lightened up a little bit? mother! is a much bigger question mark. The film would have to be a decent enough box office hit/awards player AND have enough material that can be translated into a house, which is hard to say given how little is being revealed about the movie.
There's still a lot of other Blumhouse IPs that can be used too. Ouija has enough material for a house, and they might have the props depending how far the scrapped Blumhouse scenes got. Paranormal Activity is another one, but Universal doesn't have the rights to it and would the public even care about it now? Then there's stuff like Get Out, Split, and The Visit that would work in a mashup house but maaaaaaaybe not a full-fledged house.