From Rabbit Chat, I’ve found each of their otome game scene with Mitsuki (the supposedly woman crossdressing as man) :

Sougo x Mitsuki : uhm… they’re fiancee… who is quite lovey dovey before got into a fight in the middle of the story (due to yamato :v), do i need to say more?

Riku x MItsuki : the hero x heroine. the ssr card gakuen mitsuki where he’s feeding someone a cake implying the doki doki lesson he has with riku (so possibly the one in the card being fed is riku POSSIBLY)… also in the story, he is the only one who knows riku is an android

Iori x Mitsuki : iori gallantly rescued mitsuki from being captured by yamato despite being one of the villains and swooned him lol

Tamaki x Mitsuki : mitsuki-sensei is the only one the cool senpai tamaki could open up to. there was a scene where the cool senpai tamaki is picking up a puppy in the middle of the rain and mitsuki offered his umbrella (so otoge lol)

I have yet found yamato x mitsuki or nagi x mitsuki supposedly otoge gakuen scene :v