As Zepy himself observed the revelation of Ritsuko's cousin being a trap comes on the heels of the 16-year-old idol mother. That's two out of three. At this point I expect that Eri Mizutani has a certain controversy built into her as well, we just don't know the specifics yet. She's a former hikki, but that doesn't seem sufficient alongside Ryo. I will be disappointed if she doesn't moonlight as an assassin for hire, or something else more outrageous than merely being a reformed hikki.

UPDATE: DiGiKerot reminds me (with a comic!) that "hikikomoris are often associated with traits that are, perhaps, considered more deviant aspects of our hobby." Right-o.