In the comment section for chapter 10, I said some stuff about how I thought the girls were named after the gospels. Clearly barking up the wrong tree entirely there, rip to me.
It makes sense that they'd be named after sweets/food though, as most (if not all?) of Kuroha's characters have tended to be.
Ruka having the same name as one of the gospels does feel strange if it was a total coincidence though.
("Eguchi Chihiro" also doesn't fit any of the other "patterns" I identified, save for being 4 characters. My goose is so cooked)