I think oro will use the last two zetsu clones to learn all the info that zetsu knows considering the fact that zetsu watches EVERYTHING. as for the second one, i believe he'll use it to help sasuke unlock his rinnegan.
What do you guys think? :P
I belive tobi is a zetsu clone. (Black and white) Listen to the way tobi talks and then listen to the way the masked man talks. also because of this.
http://www.youtube.com/watch?v=JdgJqaz7p7M
Which is why he can easily move through objects.