I, Giorno Giovanna, am a Beastar

Jotaro and Abbacchio look pretty different

Yes they are

What did Part 6 do to them? (Yes, I know that Abbacchio died in part 5, I'm just assuming the reset in Part 6 also brought Abbacchio back, even if he's unrelated to the story of part 6 (I haven't read part 6))

And it was now I realized 'The House With a Clock in its Walls' made a JoJo reference about resetting the world.

Anyway it may have brought every death in JoJo back to life. So that means Dio wouldn't have Jonathan's body, but considering his body may have limited Dio's vampiric abilities (unless he actually was being such a dick), Jotaro would've actually had a hard time dealing with Dio.

Dio would've still procreated Giorno but Giorno would've been born with a villainous mindset and could've, out of any, inherited The World, overthrown Diavolo, or team up with him. Giorno could have also inherited vampirism from his father.

Jotaro might've not actually made it into part 4, but Dio may have instead, though I don't see what kind of antagonistic role he would play.

Oh wait, he could've already been eaten by the Pillar Men going on in his vampire life.

So what now?

I mean, in the part 6 reset, everyone essentially dies, so technically, no one in the original universe survives.

Then what about Johnny?
That probably explains Josuk8's amnesia.

Isn't the SBR universe separate from the original one?

Oh, so Johnny, being in the AU, and Josuk8, after the reset, each made their own Joestar bloodline? However that's a concept though.

The Saint's Corpse apparently influenced part of JoJolion, apparently. Josefumi doing Equivalent Exvhange with Kira made Josuk8. Kira is related to Johnny. Only part of Kira fused with Josefumi I think. Guess they both made 2 bloodlines. JoJolion is also a sequel to Steel Ball Run.

Using this YouTube thumbnail, there is only one existent bloodline; the other we'll just have to wait until part 9 perhaps. The other bloodline could be a vampire Joestar, since we already have a Brando-Joestar (Giorno Giovanna) and a vampire Brando (Late PB Dio Brando). Or maybe in part 9, considering JoJolion a relative to DIU, Araki can star Shizuka Joestar, the "invisible baby", and fight alongside the vampire Joestar.

I would assume that they would feature a Joestar from a different part. Still, nice idea