Dude, there is a ****ing good reason why Kishi made Edo Hokage immune to Genjutsu. Do you think they will dance or what? Minato will get his arms back believe it! No matter how, maybe Orochimaru will break out off the genjutsu with Sasuke's help etc. And use Edo Tensei again on Minato. Or his son the Jesus will bring him new Arms (he said cleary ,, i fell i could do anything" ) and where is the Problem that Minato would be above Hashirama ?even as a Jinchūriki he has good chances and we just know 40-50% of Minato's Skills about Hashirama we know everything. About Hiruzen we know everything.
Just Tobirama and Minato are left to show us there Skills, Minato showed not much of his power