The 3rd Raikage alone should be able to fend off the 5.000 Zetsu's on his own like he did against the 10.000 fodders during 3 days. With Ay thrown into the mix, i dare to say they finish them off.
The Budha is easily taken down by the combined efforts of Onoki and Muu via double Jinton.
The kages have some quite intelligent people among them + numbers on their side, as the fight prolongs i'm sure they would figure out how Obito's Kamui works.
Imo they can pull this off.
