Wanted to clarify a few things.
I can't believe THEATER DAYS and LIVE ON ST@GE (and the SideM anime!) are happening in the same year.
This is unconfirmed. Theater Days is coming out this year, but Live on St@ge has no release schedule planned out at all. Perhaps it'll come out to coincide with the anime?
Unlike Theater Days, LIVE ON ST@GE is made by the same developer that made Deresute iirc
Actually, Live on St@ge is being handled by a separate developer from Starlight Stage and Theater Days entirely. Cygames has nothing to do with the SideM franchise, let alone Live on St@ge.
which might explain why Million Live has yet to get a crossover event with Granblue Fantasy (iirc Cygames owns Deresute, Raibuste and GBF)!
It has nothing to do with developer. It has to do with platform, though. Cinderella Girls and SideM are both part of the Mobage platform while Million Live is part of the GREE platform.
And even when taking developers into consideration, Cygames did not make SideM. They did develop Cinderella Girls, hence the large number of crossovers between Cinderella Girls and Granblue.