I think it's waaaaaay too early to start anything Project Jupiter related. Also 876 appearance makes no sense at all in this anime. Worst episode ever in that they're still doing filler plots while trying to introduce a new story arch.
I agree; for one, I'd like the story to pick up and actually see some real idol events happening rather than have 9 filler episodes. Also, it seems like some characters have gotten a lot of spotlight while others have been neglected in seeing them develop.
However, we're getting close to the halfway mark in the series, and usually by then, a new story arc is introduced. I'm glad Jupiter appeared because frankly I think it's about time we see some of 961pro. I want to see CONFLICT. Conflict gives us plot. And I think it's about time for some 765pro vs. 961pro action, no?
Frankly I don't care about 876pro appearing in the anime but I guess it's nice they gave them a cameo since I thought for a moment they had totally disappeared off the face of the earth and was worried everyone had completely forgotten about them.