With this upcoming battle being hinted as being the biggest battle in One Piece world there will be plenty of characters to fight. There's Orochi forces, the Beast Pirates and Big Mom pirates. It doesn't stop there. There's a good chance the Marines will show up because of SWORD and CP0 should still be somewhere in Wano.
With a force that large the Pirate - samurai - minks alliance will need some help. That's the reason I believe the straw hat Grand fleet will arrive to help.
With all that said, I believe Luffy, Zoro and Law vs Kaido. While Kid, Killer and Sanji fights Big Mom.
Even though I know Kid wants revenge against Kaido I don't think he's going to be as useful in battle as the other three. Luffy have advance COA level 2 that should allow him to bypass Kaido scales, Zoro sword strength and haki should be enough to injury Kaido and Law DF will allow him to bypass Kaido durability as long as he's not using haki to stop it. Yes, Law attack may not hurt Kaido but it could be used to give the other two an opportunity to hurt him. Unless Kid has advance CoA level 2 I don't see him damaging Kaido.
I think Kid will fight Big Mom because she's going to want revenge against him for entering her territory and stealing whatever he took from her. In the latest chapter it appears to be an egg. Killer will more than likely follow Kid. That leaves Sanji who Big Mom should still be mad at. Sanji should still be mad at her.
With a force that large the Pirate - samurai - minks alliance will need some help. That's the reason I believe the straw hat Grand fleet will arrive to help.
With all that said, I believe Luffy, Zoro and Law vs Kaido. While Kid, Killer and Sanji fights Big Mom.
Even though I know Kid wants revenge against Kaido I don't think he's going to be as useful in battle as the other three. Luffy have advance COA level 2 that should allow him to bypass Kaido scales, Zoro sword strength and haki should be enough to injury Kaido and Law DF will allow him to bypass Kaido durability as long as he's not using haki to stop it. Yes, Law attack may not hurt Kaido but it could be used to give the other two an opportunity to hurt him. Unless Kid has advance CoA level 2 I don't see him damaging Kaido.
I think Kid will fight Big Mom because she's going to want revenge against him for entering her territory and stealing whatever he took from her. In the latest chapter it appears to be an egg. Killer will more than likely follow Kid. That leaves Sanji who Big Mom should still be mad at. Sanji should still be mad at her.