Mizuho about 9 years ago As she is the only red head in the game that i know of, i believe this is Amane.
EB about 9 years ago The artist doesn't tag Amane at all (if he intended that, you think he would since the red-haired girls is featured prominently), and I believe he calls this character "Hakase". May be an original character if it's not someone from the game.