1. Just like Rentarou, I automatically thought Mimimi was talking about Nano.
I mean, let's be real. Nano is is statuesque stunner of peerless and proportioned sto8c beauty. Plus, her more classically oth9dox beauty is balanced by the wide range of age appropriate cute that girls like Hakari and Karane have, contrasts nicely to the more tomboyish Iku, is emphasized and equally boosts the loli cuteness of Shizuka and Kusuri(smol), yet would be a devilish combo with Kusuri(big) who is a full figured, sexy af 3rd year..... which finally leads to the pure sexiness of the more mature livers in the group.
In that sense, Nano is is basically the measuring stick for the objectively beautiful within the group.... but then, she's got her silver hair, ruby eyes, and android-like kuudere yet very passionate nature that both enhances, and keeps her from being a pointlessly static character.
2. In the series' tradition of wordplay and t4ope tinkering, Utsukushisugi Mimimi's name contains the word for 'beautiful'.... on top of it being read something like 'too beautiful = me, me, me'.
Kinda obvious when you consider she's a surface level narcissist who is only surface level in that her narcissism is simply a tw8sted form of pride towards the pursuit of 'true beauty', which 8s built up over time and meticulously maintained.... on top of a surprsingly fragile and easily wounded girl wanting to be accepted by somebody she saw as her equal....
Though now, I gotta wonder how much work Nano actually puts into her feminine charm and general beauty.
Hakari I can see patting in the effort, but how much does Nano do to look so effortlessly gorgeous?