Shiho is secretly a sadistic dommy mommy type? Why, that's perfect for a weak-willed protagonist like Yuuichi. I'd bet he's secretly an M anyway. I can see him getting pushed around by her. He already lacks the spine, guts or balls to stand up to any of these girls so I'd say he's already halfway there to his masochistic awakening. He'll fit right in as the submissive male lead to her dominant female lead.
But honestly, the sweet, kind seiso type girl Shiho has going on the outside makes her more fitting to be the yandere than Kaori is, I've never seen the haughty ojou-sama types like Kaori to have much yandere potential. In more typical cases Shiho would normally be the yandere and Kaori the sadistic dommy mommy (it's usually the rich girl types who are like this). Did the editor suggest to swap the attributes for novelty value or something? It's a curious choice for sure, but I don't think it fits well.
As expected, here's the reversal with Sei being scared of the haunted house, but Tsukasa doesn't seem to be completely fine either. Good thing she's uh, able to distract him well enough that he won't freak out.
