Hahaha I'm glad you liked it! To get ending 8, just talk to the twins and answer "yes" when asked to become their pet
Nah, they are just decoration to show that, indeed, that is the insanity hall for a reason hahaha. Actually, Alesa was supposed to say something related to the stairs but it seems I forgot to activate it. She just said somethin like "why are there stairs in the middle of the room? They don't lead anywhere though..."