During the circle scene of OP 2 (Yumeiro Parade), I counted that there are 12 girls in the circle. However, all the most prominent members of their group are just 11 (from what I know). Here are their appearances in order:
Kujou Karen
Inokuma Kota
Inokuma Mitsuki
Inkkuma Youko
Komichi Aya
Karasuma Sakura
Kuzehashi Akari
Matsubara Honoka
((Who is this?))
Oomiya Isami
Cartelet Alice
Oomiya Shinobu
Who appears between Honoka and Isami?
P.S.: This character's hair is similar to Shinobu.