Tobi and Kakashi
Tobi knows Gai and Kakashi personally. Those Naruto towards who still think Obito and Tobi are one in the same, looks like there's still hope.
But whether Tobi is Obito right or not, it doesn't make much different information. The guy is the villain, plus he's pretty crazy. And he being a former comrade shouldn't change things. To Kakashi, Obito died long ago. And his face now might look so messed up from all the eyes etc. that even without the mask they wouldn't recognize him
Well, the confirmation that the 10-tails isn't some omnipotent beast that lived beside humans, but in truth is GOD, something that created all and thus humans as well, is quite important. It is the beginning as well as the end and one of the reasons why I posted that image, since that thing had similar names to what 10-tails was called (although in it's case, it was a being between monkey and human, one that directed the course of evolution).
Kakashi wants to try something! His hand is up in signature raikiri fashion, you know what?! He knows he can strike tobi with a physical blow! Reviving the ten tails just might cost him the ability to phase momentarily! He did not use his eye on naruto! He batted him away! Ya, was to change his direction away from maizo but kakashi most definitely is up to something THAT WILL WORK!!