I don’t see Luffy getting more than three billion bounty – I feel like it’s safe to say that his final bounty will be along the lines of 5.6 billion (Oda loves puns, and it’s slightly more than Roger’s bounty), and there’s no way that beating Kaido, as impressive as that is, will increase his bounty more than finding One Piece and becoming the Pirate King would.
I’m guessing credit for beating Kaido and Big Mom is going to be split between him, Kid, and Law. Luffy will get the lion’s share of the credit, since he’s doing most of the work and Big News Morgans will likely claim that Kid and Law were working for Luffy, but I figure those two are probably going to get up to a billion in terms of their bounties.
My guesses are:
- Luffy: 3.5 Billions
- Eustass Kid: 1.8 Billion
- Trafalgar Law: 1.7 Billion
- Nico Robin. Robin’s greatest threat is always from the World Government, since, from the age of eight, they have ruthlessly hunted her. The persistence of the World Government and their view on her being a threat would not cease even after a timeskip passed, as during the Raid on Onigashima, the World Government send numerous ships out to Wano, openly to annexing Wano under the World Government, but secretly having a second order for its agents arriving there with the capture of Robin, still seeing her as a threat to the Government and the secrets its trying to withold from the world. This order was later seen being put into action, when some CP0-Agents chased Robin and Brook in the castle, with Robin wondering why the CP0 was in Wano and her being unaware of her being still a thorn in the eye of the Government. I could see Robin getting something absurd like 1.5 Billion bounty.
- Zoro: 1.4 Billion. He’s the right-hand man of the current 5th Emperor. He has defeated Kaido’s strongest Commander. I can see him gaining a slightly higher bounty than King.
- Sanji: 1.35 Billion. Slightly less than Zoro, slightly higher than Queen.
- Yamato: 900 Millions. This is just a guess, and it’s absurdly high for a first bounty, but depending on what Yamato does or how public that knowledge is, I could see him/her getting a high bounty for being the child of an Emperor, and betraying that Emperor to join the Straw Hats if that’s what winds up happening.