At least some of them are definitely at least partially forged, and the DKIM headers for none of them have been released, AFAIK. At least some of the released screenshots of emails are obviously doctored (text that should be level with the text next to it is not).
The last one seems plausible. It's pretty clear that Hunter implied that he could influence the US government in an effort to make deals. It's less clear that his claim was true.
Why do they seem obviously fake? Why does it seem so reasonable that Hunter Biden would fly across the country to have an Apple laptop (or is it laptops?) repaired at a shop that doesn't specialize in them, that Mr. Biden forgot about the laptops and left them behind (and full of evidence), and that this shop just happened to be good friends with Rudy Giuliani? That this story just happened to break right before the election in the aftermath of a long series of conservative conspiracy theories about Mr. Biden (https://www.nbcnews.com/tech/security/how-fake-persona-laid-...) in an election where foreign influence has been frequent and obvious?
From what I've read about this story, it has indeed all the evidence of being a complete fabrication, and none of the evidence of being true. We only have Giuliani's honesty to trust that it's true.
There is no claim. It’s all misdirection. All you have to do is cite some known figure supporting the mere possibility of some vague non-claim and it becomes the branch that ideologues desperately cling to. No one is overtly making any of the logical claims you posit above. Not Biden nor his family or campaign. They simply need to use buzzwords like Smear, Russia, and 50 high ranking officials, and that’s all the sheeple, especially those in the SV echo chamber, need to hear.
The Hunter Biden emails are fake? or that they are real, but Giuliani got them from Russian agents?
Or that they are real, but "the big guy" doesn't refer to Joe Biden?
Or that they are real, but Hunter Biden was just saying shit, and Joe didn't actually do any of these things?
Any but the last claim seems likely false to me, pretty hilarious to see so many on the thread arguing otherwise.