They would have killed Sasuke.
Pretty much this.I'd say Hashirama would make the others not interfere.
Prime Hiruzen would have neutralised them both though.
The question is, would they stand a chance against him? I think it would be a interesting battle.
Most of them don't to be honest.
But then there is Hiruzen there......
I think they'd believe Naruto would win, so they wouldn't want to interfere, except Tobirama. He'd love to try to fight an Uchiha again.
They would have sided with Naruto to beat Sasuke, normally I see Hashirama staying out to let them handle it but he's not going to this time when the fate of his granddaughter and the alliance just to a fight of a non-fully powered Naruto. Tobirama already showed that he would strike down any bad guy before him or at least try too.
What can Sasuke do to the Edo Hokages? He have no sealing jutsus so they'll just regenerate and his coreless CT doesn't have fear of being used on beings not 100% chakra but of flesh or whatever Edo's are made of. Sasuke never shown the ability to pull out souls and still never mastered his Rinnegan so not seeing that happen until it does.
The Hokages can serve as the ones who make Sasuke use a lot of his chakra and the Bijuu chakra against. They'll have clones that can help them do this and Minato can teleport Indra's arrow and Susanoo arrow away while Tobirama teleports Bijuu+PS away and Sasuke used PS to hold the Bijuu chakra. The Hokages are all smarter and have more battle experiences than Sasuke so coning up with such strategies isn't hard to see. That's why Sasuke said he wanted for all those who could stand in his way left but Naruto.