I think I finally learnt the characters of each band. Correct me if I'm wrong.

Poppin'Party : Toyama Kasumi, Tae Hanazono, Saya Yamabuki, Rimi Ushigome, Arisa Ichigaya

Roselia : Yukina Minato (?), Udagawa Ako (I think she's in Afterglow), Rinko Shirokane, Lisa Imai, Sayo Hikawa

Afterglow : Ran Mitake, Udagawa Tomoe (Is she in Roselia?), Tsugumi Hazawa, Moca Aoba, Himari Uehara

Pastel*Pallettes : Aya Maruyama, Maya Yamato, Chisato Shirasagi, Hina Hikawa, Eve Wakamiya

Hello, Happy World : Kokoro Tsurumaki, Hagumi Kitazawa, Misaki Okusawa, Kaoru Seta (Fleeting), Kanon Matsubara.