Well, if it's anything like Cinderella Girls, they'll add new characters, and maybe Ryo will be one of them!
...I'm going to remain hopeful that Ryo is in this somehow.
And also those people saying Jupiter will be just as important as 765 are in Cinderella Girls... They might be right, as they don't have casual outfits. I imagine Hokuto, Touma and Shouta are starters.
Also looky here, 765 makes a cameo!: