The pardon's don't hold any weight because a president can only pardon an individual for whom an investigation has been completed and enough evidence exist to go to trial, and that trial is expected to proceed, or during a trial, or after a conviction. That's the SC ruling set on it.

What they do all have though is immunity as part of the executive branch. Really, if you understand all the plays that were in effect, that was the only one ever meant to actually make it to the SC. Trump's immunity case, and it wasn't just a focus on presidential immunity, it was on executive branch immunity. As such, none of them can be compelled to turn over documents/conversations/recordings, etc., nor can anyone who engaged with them outside the executive branch unless they do so willingly turn over evidence, or enough evidence is found to convince them that they themselves will face charges unless they cooperate with the case. So this has a long, long way to go yet, and they have to prove beyond a reasonable doubt that an egregious crime(s) occurred outside the authority of the executive branch exist to compel them to turn over the listed items.
This doesn't even mean that state prosecutors will investigate the claims being made, and given the current administration, and the fact Trump is involved in this up to his head, and threat environment that exist on a much lower level of claims than this, it is highly doubtful they will chose to tackle it while Trump's in office.