There have been many predictions of team fights to put down Kaido (Luffy and Law vs Kaido, Luffy and Kid vs Kaido, Luffy, Law and Kid vs Kaido, etc.). I completely understand, why people would think that. Kaido is a Yonko, has most likely never been defeated one-on-one and is said do be basically invulnerable. But that's exactly the reason, why I think that
Luffy will fight Kaido one-on-one
Kaido's status as (right now) the strongest single person in One Piece, his incredible durability and strength and his position as one of the Yonko will be a very important obstacle for Luffy to overcome. Luffy is aiming for the title of Pirate King. If he wins such major fights only in a team-effort, how can he aim for the top like that? The world thinks, Kaido cannot be taken down one-on-one, Luffy will do exactly that and show the world who he is and what he can do. After that fight Luffy and Blackbeard will be the top contenders for the throne of Pirate King (and of course Teach will be Luffy's final opponent before finding One Piece (not the final opponent of the series!)).
Now, how will this happen? People will probably argue that right now, Luffy is still quite far from being Yonko-level, and that's absolutely true. That's why I think the final battle between Luffy and Kaido won't happen anytime soon. It will take a lot of time to get to Wano, similar to the voyage to Arabasta in the first half of the Grand Line. Luffy and his friends will travel for some time, facing several of Kaido's allies and underlings, giving them the opportunity to get stronger in the process. And it's still questionalbe if Luffy will actually fight Kaido in Wano. Maybe he will, that time actually with help, he will be beaten, he will recover, he will come back for a second round, this time one-on-one and then he will win. After that he will probably even be considered a Yonko himself, before finding One Piece.
It has to happen sooner or later. Oda himself said some time ago IIRC that One Piece will probably end within 6 or 7 years. So within the next couple of years, Luffy should reach Yonko-level IMO. And he will reach that Level by beating Kaido.
Zoro vs Shogun
Zoro vs the Shogun and Zoro vs Jack are, I think, the most common predictions for Zoro in the Wano Arc. I think it will be the Shogun, and this is why: Jack is a swordsman, yes, but most importantly he is a devil-fruit user and I think someone else will fight him (see the next point). I think it is about damn time that Zoro will face an extremely high level swordsman one-on-one. (And only a swordsman! No devil fruits!) Zoro is aiming for Mihawk, he wants to be the best swordsman in the world and I think the Shogun will be the next very important step he has to take. There has been some speculation about the Shogun's powerlevel, if he is really that strong or just someone good at manipulating other people. I think he is incredibly strong for mainly three reasons: 1. As far as we know right now, he is Kaido's ally, not underling. 2. Wano is considered an incredibly powerful nation that even the World government avoids conflict with. The people at the top have to be ridiculously strong. 3. Providing an important opponent and challenge for Zoro on his way to becoming the world's strongest swordsman. I think the Shogun will be in the top 3 or at least top 5 of the strongest swordsmen in One Piece, someone not quite on Yonko-level, but actually close and above the three calamities.
It will be a swordfight, it will be bloody, it will be brutal, we will finally see Zoro go all out. Ever since the timeskip Zoro has fodderized everyone in his way, except for Fujitora, a freakin admiral, and even there he managed to hold his own for a short time. It's way past time to finally see Zoro go all out again and he will have to do exactly this in his fight with the Shogun. At the end Zoro will be bloody and on the verge of death (like he was after his fight with Mr 1), but he will have cemented his position as someone aiming for the top.
Nekomamushi and Inuarashi vs Jack
One word: Revenge! They will not take turns fighting him one-on-one, the will 2v1 him, they will somehow manage to fight him under a full moon, they will go Sulong on his ass. I am craving for this! This heartless bastard needs to be punished and Sulong Nekomamushi and Inuarashi are the right men, sorry, minks for the job. Do I need to say more? There will be blood. Lots of it. And it will be very satisfying.
Sanji and Jinbe vs Calamities
Apart from Jack there are two more calamities and Sanji and Jinbe will take care of them. By the time Luffy reaches Yonko-Level these two should be strong enough to do that. I think there will actually be one of them, who is actually even stronger or somehow more dangerous than Jack and Sanji will fight that one, re-establishing the Monster Trio of the Straw Hat Pirates. Sanji really needs an opportunity to shine, ever since the timeskip. After that, the name Black Leg Sanji will be known all over the world.
Trafalgar D. Water Law vs X Drake
Now this is just speculation, but I think there will be more to both of these guys' pasts and a deeper connection after what happened on Minion Island. (Edit: Based on the other Edit below (Law vs. Kaido's Ace) this fight could also occur some time before the actual Wano Arc.)
Eustass Kid vs Scratchmen Apoo
Same reason as the Nekomamushi and Inuarashi vs Jack fight: Revenge. They had an allience, Apoo betrayed that allience and joined Kaido, Kid will punish him for it. Again: Blood and brutality, Kid will finish him.
Apart from these 1v1 fights there will of course be a great war between Luffy's alliance and the Minks on one side, and the Beasts Pirates and the Shogun's forces on the other side.
EDIT: Law vs An Ace up Kaido's sleeve
Going by the Card-theme of Kaido's crew there could be someone even more powerful than the calamities in Kaido's crew. Someone like this would IMO be the perfect opponent for Law and his overpowered devil fruit.
Bounty predictions after that:
Law: 900,000,000B EDIT: This is only based on him beating X Drake. He could very well do something far more impressive in the Wano-Arc or even before that, giving him a much higher bounty (somewhere between 1,500,000,000 and 2,000,000,000).
Rest of the Strawhats: Varying, all somewhere between 200,000,000 and 800,000,000B