What we know so far is:
Honoka is the Leader /Umi the Lyricist
Maki-sama is the Composer /Kotori is the Choreographer/Tailor
Nico is the Idol Adviser /Rin is the Hype (man) Girl
Hanayo is the the Ultimate Idol Fan Girl
Eri - Class President and is "Haruka" amazing (Just look at that chart!)
Nozomi is a perverted shrine maiden, stalker, and groper of unripe fruits (I approve this message.
)