Very interesting. I dont think bartolomeo is sabo though(persanalities are WAY off)
But sabo being the 7th shichibukai sounds plausible.
I firmly believe sabo is alive in some form or another. There was NO reason to show dragon saveing a random male kid, NEAR THE EXACT TIME sabo was "killed". It was forshadowing by oda.
Now sabo may be a revolitionary, or may have lost his memory, or maybe even both.
A common arguement for why sabo CANT have survived, is because he didnt come to try to save ace.
Well it took luffy 1 week from hancocks island, to get to the prison, and he was in the grandline already. If sabo was all the was across the world, then he couldnt get to ace in time.
He wouldnt rescue ace also, if he lost his memory.