I like this idea more tbh
Luffy Nika Form was the closest we had of referencing Joy Boy, but Oda was always hinting towards him with rest of Crew
Such as Chopper coming from Drum Island and introduced as if he was flying under Full Moon
Usopp's Journey is very similar to Nika as he freed Slaves, was called God and his Lies become Real
Zoro described his Heart Beats against Mr. 1 and how he feels it all that surrounds him
Brook is someone who returned from Death, Laughs a lot, loves Music and he was shown hypnotising enemies under Full Moon
And you can find such references with rest of Crew too
So it's clear to me that Joy Boy is to SHs what Oden was for Scabbards and his Family, a source of Inspiration and Inherited Will
There is one thing that connects all Crew, and it's their Ship, but since SHs are meant for greater cause which is World Changing, that means they inherited Greatest Will ever
In other words, One Piece World is a Ship, Joy Boy is its Klabauterman and SHs are the ones who Inherited its Will, making them literally The Greatest Crew of The World
As for the person who Inherited Joy Boy in a Literal Sense, similar to Momo with Oden
It's none other than Shanks
That's why Oda created Promise of Luffy wanting to surpass his Crew. That's why Oda said Shanks represent him, that's why his Presence is Unmatched. That's why he Laughed when Higuma insulted him and his Crew laughed after, that's why the Hat belongs to him, that's why he asked Roger a Secret Question after he found Laugh Tale, that's why Blackbeard is his Nemesis similar to Orochi with Momo and that's he is Luffy's Inspirational Figure and much more...
So yeah, the entire story revolves around Ship Spirit and it's what started entire OP Lore