I had issues guessing most of them, so here's the answers as guessed by pixiv... Top row: Marisa, Yukari, Medicine, Minoriko, Flandre, Yuugi, Alice Bottom row: Suwako, Rumia, Yamame, Ran, Parsee, Lily (black Lily?), Shizuha, Lunasa
It's... really not that hard, to me. The order is correct. Shows that despite the hats jokes, hairstyles, eye colors and expressions actually do a lot for the characters.