I'm surprised I don't see more people mentioning the implication of incest due to the daughter and son having the same dynamic as mother and father...
Ooki and her daughter keeping the horror vibes going. At first I was impressed with the daughter for going along with the troll on the spot, but Ooki didn't mention the name Okada until after her daughter went along with it. Even if her daughter knew from the name of the Okada kids, she shouldn't have known their father's first name and thus shouldn't have been able to deduce what the troll was. They either planned the entire encounter in advance or there's something supernatural going on...