That sounds right. It's likely going to follow the same formula as the ML manga where the ML characters are the main focus while the 765pro idols make cameo appearances (with a little bit of advice giving in the early chapters but pretty much absent afterwards).
It's also likely that the ML characters will have their own producer in the anime and not the producer from the 2011 anime (I really hate him. The CG producer was much cooler.)
So, it seems 765pro is like a minature 346pro with multiple units and producers. But, that would mean they will likely select a team of ML characters and focus on them kind of like Cinderella Girls Project. So, a chunk of the ML idols will be left out though they will make appearances again kind of like the CG anime.
I doubt they'll have a new Producer. If this is gonna occur in the anime universe (which it is), it's probably gonna be the same one from 2011. Might even give some callbacks to the movie. Although having a third (Ritsuko counts) Producer might help what with the fact that there's 50 girls rather than 13.
As much as I don't mind Cinderella Project, I hope that DOESN'T happen for Million Live. Kinda seems unnecessary since ML's cast isn't NEARLY as huge as CG's, so focusing on some sort of idol project wouldn't make sense. There could be a set roster of characters that get more focus (Mirai, Shizuka, Tsubasa, Serika, Anna, and Shiho come to mind) but splitting them into a sort of unit and only focusing on that unit wouldn't feel right, imo.