I know this much.
Kabutomaru is lying obviously about telling Tobi how to undo Edo Tensei.
He told Tobi that all you have to do is have the summoner end the technique. As they are unlikely to do this voluntarily, using a genjutsu to trick them into cancelling the technique is ideal. The sequence of hand seals for cancelling the technique is Dog, Horse, Tiger and saying "release"
^ This has to be a lie.
First of all, Kabuto has the remains of Orochimaru in him. Orochimaru is a snake, and snakes/serpents naturally are cunning liars. (snake in the grass)
Second of all, if Kabuto betrays Tobi, and Tobi were to undo the Edo Tensei, Kabuto's trump card "Madara" would be gone.
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Third of all, Kabuto's motives aren't Tobi's goals. Kabuto wants Sasuke remember so that he may unlock the many jutsu of the world, and discover the secrets of the Sage of Six Paths. This future goal would be useless if Tobi completes the Eye of the Moon plan because why the heck would he continue to do research in a fake Tsukiyomi world?
Fourth of all, Kabuto is keeping secrets from Tobi.
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^ Plus look at his face. Is that a face you can actually trust?