You cant be serious if u say that an Akatsuki member and one of the strongest Jonin in Konoha are non-factors. Konohamaru would be a non-factor and even that would be doubtful really :NO:
Tsunade kill Hidan, he doesn't phase her.
Tsunade kills Mei, speed is greater.
Tsunade kill Asuma, he will have to get close and once he does he kills him.
For Gai, Jirayah goes Sage while Tsunade distracts him, then Gai dies. Few can win against two or more Sanin.
Gai and asuma are quick enough to keep Jiraiya from going SM .. and Gates guy could even end Jiraiya ... What does tsunade have to kill hidan? oh ya nothing ..Mei and Hidan can keep Tsunade (if not beat her) Busy untill Asuma and Gai gets back ..( gai solos tsunade) so from there they win
Jiraiya is honestly the one that breaks this open...but if Gai goes 7 gates against him and maybe gets help from Hidan cause if Hidan manages to get blood from Jiraiya which he should be able to do with Gai on his side, than while Jiraiya is distratced with Gai Hidan finishes him off with the ritual. Tsunade and Mei would be a close battle 1v1 add Asuma to help Mei and they might be able to figure something out or atleast keep her at bay.
Hidan is immortal but can be disabled but if he even gets a tiny bit of blood he can kill one of them. This could be exploited by Gai and Asuma who are fast they could wound one of them then give the blood to Hidan. Also tsunade starts to fight dangerously when she activates the seal so that gives more oppurtunity to wound her. Gai is faster than jiraya when he activates the gates so he would aim to take him down fast so he can't activate sage mode. And finally Mei has two kekkei genkais both which are quite powerfull and lava release is quite versatile she would be long range support.