This is a battle between the Senju Sage Mode and the other Sage Modes, so the battle starts off with all of them already in Sage Mode.
Hashirama can use everything that he knows, which includes the Sage Art: Wood Release: True Several Thousand Hands of course. Naruto/Minato cannot use Kurama's chakra, but Naruto does have 2 clones at the ready for Sage Mode. Summoning is restricted, with the exception of the Two Great Sage Toads because Jiraiya.
They will have all their knowledge/abilities during the war (Jiraiya as of the battle with Pain), but nobody is an edo, so they can all be killed. The battlefield is also where the war is happening, excluding the Shinju and whatnots.
I want to make it so that Hashirama's size balances out with the team's quantity. I have a feeling that Hashi can wipe out the team by fisting, but I'm not sure because the team is extremely strong, and they also have 2 sound based genjutsus in their arsenal, assuming the battle noises aren't loud enough to cover it.