I was just pondering, since i was watching the battle with masked "Madara" vs Minato and some questions came up.
At the bottom left panel, we see "Madara's" left arm oozing off. But it seems that Obito's left side werent crushed during his nap time under the boulders.
And here at the bottom right panel we see his left arm intact.
Sure he was bandaged up, but not amputated like his right arm. Why is that?
This makes me think that it wasn't Obito during his battle with Minato.