Zetsu feats are very versatile so I fail to see how that makes them weak of a feat and especially giving to someone in the wrong hand like Orochimaru:
1.
Undetectable Spores: a.) While they are passively absorbing Hashriama chakra, Orochimaru can transfer it back to him. b.) They can appear at the perfect moment when needed[
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] and give enough time to bind the opponent/leave an opening[
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] before the opponent removes them. c.) Steal Hashirama chakra signature and replicate him, which he can pretend he is Hashirama clone, and back stab him.
2.
Mayfly: Almost all Mokuton would be difficult to catch Orochimaru
since he can just merge with them and attack Hashirama whatever he use as a platform [
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Manda 1 is clearly Buijuu level. I remember reading something Draegod mention, which kind of motivated this thread. When we compare to what Bunta can do to Buijuu's (via Shukaku and Kurama) and witness Manda putting that work on Bunta + Katsayu himself, its gets pretty clear. As for random snakes, they dont need to win the fight, they just need to inject the venom, which reacts to Hashirama's DNA.
As for Manda 2, he is too big for any Mokuton contruct in Base form. His weight and crawling on abdomen alone would break any Mokuton field in its path.
I fail to see how this fight is easy