Previous years have had houses both based on cultures (Tomb of the Ancients, Dead Waters, Yeti) as well as cultural monsters (La Llorona, Yeti, Chup, Tooth Fairy). I could see the Japanese house being just that, especially being connected to Demon Slayer in insider speculation even just superficially makes me think this is going to be a Yokai house. Japanese spirits, ghosts, monsters, ogres, as well as the elders who tend to them coming after us. That feels like a pretty solid recipe that the HHN team would cook up for us.