Who do the other names on the list of idols in episode 2 refer to? In episode 2, the producer has a list of idols/groups scheduled for events, and pens the Hacka Dolls into one of the slots to fill space. 



I suspect that all of these are references to other idols or idol-like entities. Going down the list:


まつだひじりこ "Matsuda Hijiriko" → Matsuda Seiko (kanji pun on 聖)
"u's" → μ's
"Sit Down Girls!" → Wake Up, Girls!
美少女ハリウッド "Bishoujo Hollywood" → Shounen Hollywood
でんじは組,etc "Denji wa Kumi, etc" → ???
ミス・カラフール "Miss Colorful" → Miss Monochrome
スーパーソニ男 "Super Soni-o" → Super Sonico
(Hacka Doll)
珂那ちゃん "Kana-chan" → the fleet's idol, Naka-chan
ワン子クラブ "Wanko Club" → ???
長森明菜 "Nagamori Akina" → ???
ゆりかおる "YuriKaoru" → YuiKaori
Square → ???


I haven't managed to figure out the referents of the four ones I've bolded above. Who all are being referred to here?
Here are some likely culprits:


でんじは組 →
でんぱ組.inc, Denpagumi.inc
ワン子クラブ →
おニャン子クラブ, Onyanko Club
長森明栞 →
佐保明梨, Saho Akari
(Unsure), maybe
長森佳容, Nagamori Yoshiro,
too 
長森明菜 → 中森明菜, Akina Nakamori (singer) Credit to @Passed
Square → Circle (Unsure)