This Theory actually also answers why Nika is Rubber, because if He was also affected by those experiments & his Body was programmed to adapt, then it was his Fights with Nidhogg that led to his Body becoming Rubber, Oda literally told us this Chapter why Nika is Rubber, and tbh adapting can be seen as chasing your dreams, so not only Races came to exist from Elbaph, but Devil Fruits too originated because of that Alpha Buccaneer Villain & his Scientist (Btw in recent chapter, it was written by Oda as Elbaf, suggesting that it might indeed be reference to Fable, further strengthening this Theory),
Kaidou/Caesar & Shiki/Indigo were always portrayed as Mini Version of Final Villain,
While Imu & Mary Geoise? They are apparently Endgame Version of Dressrosa & Donquixote Pirates,
Davy Clan are apparently New Riku Family, and Davy Jones was it's Kyros (Wasn't He cursed too?)
And similar to Dressrosa, there was an Island of a different Race attached to it (Green Bit) and that's who Kyros recruited, right?
So after Davy Jones Defeat, He went to an Island attached to WG's Territory (Red Line) & that's literally Fish-Men Island & it's indeed in Sea Underworld, so it all fits, (You can even notice how Mansherry is basically Dwarf Version of Shirahoshi among many examples),
What is gonna be Wano of Story? It's where Laugh Tale is located, where Four Poneglyphs lead you,
Laugh Tale is simply where the Treasure is hidden there, it doesn't mean it's not surrounded by a Sky Island or Wano-Like Region,
Roger Pirates probably had their biggest & possibly their most difficult adventure there, They didn't just find One Piece from first minute,
I said it many times, Main Villain of Story cannot be from within this World's Conflict, and the only place that is unreachable by this World is where Laugh Tale is Located, that's only place that you can't just randomly find no matter what, so that's where Final Villain should be,