I think someone said this awhile back but I think Tsunku can get away with making an big group made up for the kenshuusei.
Just call them HPK48

I mean, now that there's this new Kashou Egg system, and the girls actually have to go through Kashou Egg to be HPK , it wouldn't be a bad idea if HPK is declared an actual unit.
Albeit, they're still going to be considered "sub" in comparison to the actual HP units like Morning Musume and the rest, but I think we're at a point where most, if not all, the HPK are at ATLEAST decent or good.
I mean, this MV for Oheso no Kuni Kara Konnichiha is kinda pointing towards that idea, where HPK are starting to get songs and MVs more often.
Well, I'm not saying they need to declare HPK as a unit. As long as they keep getting songs and MVs I think that's enough to give them exposure or "unit" feel

Anyways, really excited for this MV!