A nice thread!
I like that finally some people are focussing on Oro. :ice:
I have no energy left to talk about Obito and Rin and Kakashi.
I have similar thoughts as MissShakra.
Oro might be needed to to seal EdoMadara (and maybe by this to stop Obito, too)
but if he is doing soemthing for the Shinobi Alliance he will ask for something in exchange.
And this is very likely to be Sasuke.
I think Oro does not have an interest in Obitos body (though it is a nice idea xd ) as this body seems not be an original Uchiha body anymore.
I could even imagine Madara and Oro met before the Obito accident, and Oro was involved in Zetsus creation.
When Obito showed up and started to act as second Madara and (hidden) leader of Akatsuki Oro left the organization.
(and was not amused that he couldn't manage to take Itachis eyes with him at that time xd).
Oro knew about Tobis identity all the time; as Kabutomaru called Tobi the fake Madara when they met.
(Kabuto could not know by himself, and if so he got this info from Oro).
And in the end I think that Oro already knew or planned that in any case of his death Kabuto will take his body and through this way he could survive.
