I'm just bringing out a hunch here, about the Cloning part. Madara said that the Clone was one of Hashirama's Jutsus, which means it's most likely a Moukton clone. Kind of like Yamato's one, but he's not exactly at Hashirama/Madara level of Moukton. Anyway, I personally think there could be a possibility of that specific clone jutsu being tied together with how Zetsu clones himself/feeds of people's chakra and turns himself into them. I mean, it sounds really stupid, but they've both got Hashi's DNA after all. And besides, Zetsu is the land itself, so shouldn't be much of a problem for Madara to Clone himself wherever he wants if it's the same kind of jutsu.