I'm just gonna imagine the doujin Hakuna stole was at least a OfficeGirlxFutaGirl doujin, or else someone's gonna be in SO much pain. Also, Makoto's friend should die. Period. Don't like him. GIVE ME MORE HIBARI!
... I tried to google the doujinshi because I misread your post, thinking that it was a specific one you were referencing. I am sad now.
I think Lord Atobee is Aizen, and all of this is his nefarious plot to escape his sunflower jailer. And hopefully to prove that the cutest girl is in fact a girl.
Shinozaki is one of my favourite protagonists in anything ever.