NAMI
Nami has already mapped all the areas that she has traveled, and it can be assumed that she will create a world map once the story is over. At the end of the series she will be the best navigator of the world.
Nami is already a smart woman, capable of manipulating the weather to a great degree. With Zeus, she’s going to be a truly fearsome opponent!
Her final bounty will reach at least 500,000,000 Berries
BROOK
Soul King Brook was the real MVP of the Whole Cake Island even if we do not know yet if his bounty has increased or not.
I think his final bounty will be about 600,000,000 Berries also due to the fact that he will be one of the strongest members of the King of Pirates’ crew.
CHOPPER
Somewhere later in the series, closer to Raftel possibly, Chopper realises that Luffy is dying from the very same disease as Roger did. He then dedicates his time to try and save Luffy, suceeding by finding ways to cure this incurable disease.
The World Government will realize the real power of Chopper and will begin to see him as a serious threat and not just a pet.
His final bounty will reach about 650,000,000 Berries
FRANKY
Franky is the strongest crew member after the Big Four (Luffy, Zoro, Sanji & Jinbe).
At the end of the series Franky will have fulfilled his dream to create and travel with a dream ship which would experience countless battles, can overcome extreme hardships and can reach the end of the Grand Line.
His final bounty will be at least 700,000,000 Berries
USOPP
At the end of the series Usopp will be a brave warrior of sea and the best sniper of the world. As a Commander of the Pirate King he will have a final bounty of at least 900,000,000 Berries.
NICO ROBIN
At a young age, Robin acquired a bounty of 79,000,000 Berries for having the ability to read Poneglyphs, which told of the Void Century. In the current storyline Nico Robin is the only person alive who can read the language written on poneglyph tablets. This alone is enough to make her too big a threat to the World Government.
At the end of the series Nico Robin will be the one to learn the true History of the One Piece world including the Void Century. Her final bounty will reach at least 1,000,000,000 Berries.
JINBE
At the end of the series Jinbe will be on of the 3 strongest Commanders of the Pirate King.
Since the 3-4 strongest Yonko Commanders have a bounty of about 800,000,000-1,100,000,000 Berries, his final bounty will be about 1,200,000,000 Berries.
SANJI
As the third strongest member of the Pirate King’s crew, Sanji will be one of the strongest characters in the the world at the end of the series. He probably will be the fastest fighter of the world and his final bounty will be about 1,500,000,000 Berries.
ZORO
At the end of the series Zoro will be the Greatest Swordsman in the World and the right hand man of the Pirate King. In terms of power he will probably be Yonko level and his final bounty will be about 2,500,000,000 Berries.
LUFFY
Currently, Luffy has gained a bounty of 1,500,000,000 Berries, the highest known bounty in the series and he has unofficially been titled the “Fifth Emperor of the Sea”.
At the end of the series he will take down the World Government and Blackbeard and will become the Pirate King.
His final bounty will reach at least 5,000,000,000 Berries.