I was just doing my periodical reread of More than Friends/K&A and suddenly one classmate face seemed oddly familiar, the one in the middle panel on the right.
So I did a quick search through some of Mochi's oneshots and bingo! Seems like she actually reminded me of the gloomy "top" from Christmas Overtime. Almost identical haircut, face, eyeshadow... pretty much the only difference are the hairpins, guess she simply doesn't wear them in job and/or stopped wearing them after graduation. Okay, maybe I'm just overthinking things, but knowing Mochi, there's a reasonably high chance she was meant as a same character, for all we know.
Oh, and I'm sorry if somebody has already pointed this one out before, I never noticed... -_-