Idolmaster animation is what exactly happens when otaku fans of the series is in part of as an animator.
The reason why Takane's episode came this late =
IN ORDER TO MATCH WITH THE DATE WHEN FULL MOON APPEARS.
Makoto's episode (17th episode) aired on 10/28 =
十月二八日 --> if you combine all those characters, it becomes 真日 --> The day of Makoto
Plus, they animate doujin setting of characters. No comment.