It's honestly hard to say...
I don't believe that the Edo's are as effective when they are being controlled. We've seen several strong shinobi falling, despite their incredible hype during the manga.
I believe it all depends on what happens with Sasuke. No doubt they will tell him what happened through out the years, and depending on what his actions are will depends greatly on what will happen. Let me explain why i don't think oro will control them.
Orochimaru may have the power to control them, and unlike Itachi they don't have powerful eye's to escape the Jutsu, even if they have the ability to do so, they wouldn't be able to do hand signs as they won't have control over their actions. So, this would indicate that they will be under his control, now personally i don't think this will do much good, since i doubt Naruto would sit back and let his Dad and former Hokage be a puppet.
I believe that sasuke will want to take madara down, which will cause the hokages to want to fight. Sasuke can't take Madara down alone, never mind with Obito and the juubi. I believe that Orochimaru, will let the hokages move at their own will, which will be the end of the war, because like i said... There is no way in hell Naruto would let sasuke and oro fight even madara while having control over his dad.
Sasuke will fight with naruto, to defeat Madara & Obito, although i doubt they will have much to do specially with Minato & Hashirama having such a huge grudge on them both....
I believe the hokages will fight at their own free will.