Nah, the one's left is Sarashiki sister, and mentioning them having an arranged Marriage isn't too far-fetched, as you said.
Adults also have their moment of hilarity, such as Josh and Chifuyu have a drinking competition, Iori and Yamada has to drag them and dump them in nearby (love) hotel, as per usual Yamada is imagining something dirty, while Iori is confused (he's even denser than canon Ichika). Chifuyu is not amused when she's sober
