Wow, if Usopp defeats Trebol and Sugar by himself ...
I'm going to be really excited to see how everyone else improved during their two year training if Usopp defeats (I'm guessing, Vice Admiral level) Sugar and Trebol by himself ...
Especially since Franky took out two members of Donflamingo's crew alone outside of Punk hazard ... (I'm guessing they both were also Low-Mid vice admiral levels, buffalo and baby 5 )
Also wow, I guess Kyrus i.e. Kuros isn't royalty and Rebecca's mother was the royalty (Rebecca's mom was actually King Riku's daughter, as Kuros is the son-in-law).
I guess, it puts Rebecca getting the fruit and becoming a next member prediction of mine on shaky grounds.
Unless both Kuruos and Rebecca end up joining the crew but, King Riku is old and needs a heir to take the throne so it seems that idea is bunk.
Possibly that Bartolemeo will abandon his crew and join and maybe Violet as well? Then again, Violet said her father was fighting so she might be the direct descendant for the throne and would allow Rebecca to leave the island since her auntie violet would be next in line for the throne and become queen.
But, chances are it'll only happen if the Toy soldier (Kuros / Kyros) dies fighting in this arc