So pretty much, Black Zetsu been manipulating the Uchiha Clan for the entirety of their existence?
Nah, once Kaguya is taken care of, we'll probably get the final fight between Naruto and Sasuke.
If Madara comes back, he'll probably help out against Kaguya and sacrifice himself to stop her or something. After all, now that he knows he was just manipulated into following the Moon's Eye Plan he'll probably be remorseful for causing all this trouble.
Orochimaru? Sorry breh, but he hasn't been relevant since Part I.
After all the Ls he's taken since the timeskip (sonned by Naruto, Itachi, Sasuke, then Itachi again) he can't be taken seriously as a villain anymore, plus there's too many people walking around more powerful than him. If Orochimaru tried something, any or all of Naruto/Sasuke/Kakashi/Obito/Madara/Any Hokage/Any Kage/Bee should be strong enough to beat him.
You might as well consider Orochimaru a member of team Taka at this point. Dude is basically just one of Sasuke's followers these days.