I feel like the current erotic events are a bit out of order.
I think that when we manage to obtain the "teddy bear" we should obtain a scene with the sister (Because it's what we are looking for picking her quest), maybe something minor as watching her masturbate or her watching the MC using the "toy", but a scene with her nonetheless and if we manage to finish the whole factory dungeon or if we sell X number of chips/pay a price/get a secret item("Special coupon") as a reward for completing the dungeon then we get the scene with Alyssa but, as I said, as an optional bonus for going the extra mile or just as a secret.