I would change this part:

"Kiri has access to Nibi"

Changed thanks :D was originally gonna go with a different pairing ^^'

What about the 5-tails, isn’t Han also part of Iwa? That way Kumo can also bring Bee into the battle and we can have a 2v2 Jinchuriki fight.

I think that A would win the battle against Onoki if the Tsuchikage doesn't pull out particle release but since Onoki needs to charge it I could see A taking the time to seriously injure him also we haven't seen Onoki use much except for earth release and particle release. as for the tailed beast I would say that the 4 tails wins this one. while Yugito is proficient in taijutsu, Roshi's shield would most likely force her to fight from a distance which he would be good at as he can throw lava around their battlefield. The hidden cloud also has a better economy than the stone, an equal amount of military power, but lower population, which shouldn't matter that much considering most of their ninja have a nature transformation advantage. I honestly don't see the stone winning the battle unless Onoki wins against A because A would most likely try and deal with Roshi after beating Onoki.

Okay so, truth time? I completely forgot Han was from Iwa. However, conveniently for me, it seems that he's one of the few jinchuriki who had already been collected Pre-Shippuden. So Iwa wouldn't have access to him if they wanted to.

Also, apparently, they hated him and treated him badly, so I doubt he'd come running to help them.

Also also, I doubt A would ever let Bee leave the village.

Yeah, this is more or less what I guessed the outcome would be.