I think in the midst of all these new chapters people are forgetting about how strong Kabuto was.
He had DSM, Sound Five abilities, Orochimaru's abilities, plus Edo Tensei. Who could beat that?
Itachi arrogantly claims to be Kabuto's weakness. Hashirama is the God of Shinobi but let's be honest, neither of them could beat him.
I think Prime Kabuto would even give the So6P a run for his money.
You're including Edo Tensei and saying it would beat Itachi and Hashirama, and yet Kabuto was so confident in his abilities that he didn't bother to call any of his warriors to stop Itachi. What makes you think he'd be less foolish a second time around? Itachi wasn't being that arrogant when he stated that he was Kabuto's foil, Kabuto actually agreed with that statement and admitted that out of all the Edos he summoned, Itachi had the best chance at that moment of stopping him. Itachi was actually very humble in that fight and disagreed w/ all of the good things both Kabuto and Sasuke said about him.
Kabuto advantages:
-Said he wouldn't kill Sasuke, but was willing to attempt to injure him in order to distract Itachi
-The cave reacted to sage mode chakra
-Had the same abilities as Suigetsu, Karin, and numerous other shinobi
-Can go all out on Itachi, considering that he's an Edo
-Sealed off vision
-Sealed off hearing when using a few of his attacks
-Sensor
-Essentially an Uchiha tank
Itachi disadvantages:
-All of Kabuto's advantages
-Sasuke being there. Every time he was injured, Itachi was protecting Sasuke or concerned with him. Even Kabuto stated this.
-As an Edo, you are not brought back at your full power
-No Yata Mirror
-Cannot use full version of susanno due to cave being cramped
-Cannot kill Kabuto or else Edo Tensei will never end
But due to Kabuto's god complex, he still lost to Itachi's technique Izanami. Which is somewhat embarassing because moments before the battle, Kabuto remarked that there was no way for Itachi to catch him in a genjutsu and that he wasn't losing to him.
On a 1v1, Edo Itachi would have won and he did nearly all of the work in that fight. In fact, Edo Itachi already beat DSM Kabuto. I would even go as far to say that if Kabuto didn't have the location advantage, then even alive Itachi would win. The stamina argument doesn't rely fly at all, considering that even w/ Itachi sick, dying, and holding back, he and his chakra pool still outlasted Hebi Sasuke. He would make the fight go quicker in a 1v1 and not need to hold back this time.
Hashirama...I'm not even going to explain how he would win against DSM Kabuto in a 1v1, it really isn't needed.
Don't overhype DSM Kabuto lol. He's losing to both of these shinobi.