shoooting ur theory down Kal, imo i dont think Mihawke has really ever seen WB before.
1st the way they tested eachother, Mihawke Id expect wouldnt need to test WB if he'd ever seen WB in action before.
2nd they didn't exchange any words between eachother of familiarity.
This shanks and mihawke duel must have been quite a legend that made widespread news for the whole world to know about or something, like it might have decimated an area up like Black Beards vs Aces fight.
Also that pirate king stuff, didn't Rayleigh say that Rogers only got the Pirate King title when he was about to die? Sounded to me like it was a title they put on his death bed, he didn't really LIVE as the pirate king, but he's remembered as a pirate king.
Edit
On topic tho, maybe nothing ever did happen to WB's crew mates, Im gathering your using examples like Rayleigh to judge how old other pirates from Rogers days would look, but maybe Rayleigh was old even for Rogers crew, if rookies from Rogers days are ones like Shanks and Buggy, Mihawke maybe, perhaps Crocodile, even Moria and Kuma, Sengoku, and none of them look all too old.
Maybe most of the division captains are original crewmates and Whitebeard took them all in young, I mean he's quite big on his "children" theme.
Whitebeard might just be unhealthy, and Sengoku doesn't look that old.