Haven't finished last season yet, but I thought that I'd watch some of the Summer offerings.
Phantom of the Idol ep 1
There's a male idol group with 2 members and a girl as our 3 leads, just like Heroines last season, but that's as far as the similarities go. This seems it'll be comedy focused and everything on the production side doesn't quite reach the same standard either.
Luminous Witches ep 1
Only in anime can you get cute witches from a variety of countries who can't fight in the battle against an alien invasion, for various reasons, join together to form an idol group all set in alternative 40's London! Art is very good and the ED which will be the OP was nice, so the songs will be good.
Digging a little deeper seems it's a spin off of the Strike Witches franchise, which I haven't seen, but I don't think will be a problem story wise.