After re-reading the latest Arc in the Manga, I have come across evidence that Tobirama cannot be effected by those black orb things
As you can see, he was completely cut in half (All part of the plan)
In the next couple of chapters, minato gets his arm cut off.[/I]
It is then explained that Obito bypasses Edo tensei
It is clearly explained by the Legend himself that It turns edo tensei to nothingness, but he wasn't effected
Tobirama isnt effected by Onmyoudon,iz manga proofs.
Edit: The title should be "Tobirama is invulnerable to Onmyoudon. Meh bad.