As long as Orochimaru's current body dies and his whole 'still able to be revived via curse marks'
doesn't count as surviving and thus winning, then Gai slaughters.
And in before someone tries to say Katsuyu protects them from 8 Gates.
Umm Sannin Oro J-man and Slug Princess take him out before he can go 8-gate
Tsunade can't die and Katsuya heals them
Orochimaru seems immortal somehow and knows countless jutsu
Jariya Sage mode and Frog gengutsu game over
Guy is really good but give him Kakashi and they would last longer
Idk, it's hard to say. I think he could stalemate Jiraiya and even defeat him without going 8th gate but Orochimaru and Tsunade are massive tanks and if they're running support for Jiraiya it'll make things way harder for Guy. He might be able to suicide bomb them with the 8th gate but even then I could see Orochimaru and Tsunade tanking it, especially if Orochimaru uses the Triple Rashomon.
Katsuyu isn't saving anyone, Rashomon definitely isn't saving anyone. Eighth Gate Gai slaughters them all without any difficulty whatsoever. If you restrict the Eighth Gate the Sannin take it.
Also at no point did 7G Gai have JJ Madara on the run.
Lol at Katsuyu saving them, that's really fun when a 3rd or 5th Gate Gai is already too fast for them and would easily speedblitz them, they won't have the time. And anyway Katsuyu is vaporized with Asa Kujaku. 7th Gate Gai is already more than enough to rape them, Gai doesn't need to release his full power and sacrifice his life to defeat them.