I think kakuzu with full knowledge has a very good chance of beating the six paths. He would first go to take down the reviving one.
He doesent need to use jutsu, he just has to use those thread things.
Now deva is a main problem but heres thing, kakuzu has 4 of those masks. If one of the masks attack, he will use shinara tensei, but now there is a 5 second interval for his shinara tensei, and there are 3 other masks that can attack him!
So preta path will absorb the attacks, but so what, kakuzu needs only those black threads to wrap preta path up and slam him hard to finish him.
Then deva path will use shinara tensei on him etc etc, but the thing is, with the reviving path and preta path dead. Kakuzu can just use the combination of 1 mask attacks him, he uses shinara tensei, the other 3 masks attack him. Asura path is pretty useless because he has that body hardening technique.
As for the animal sommon, he will be killed too after the others are done.
I believe the 6 paths will only beat him if they use chibaku tensei