couple issues on the pardons would be broad-based pre-emptive and validity (based on signature/authority)
not sure if Brookings is left, center or right-leaning, but my suspicion is that there are a LOT of left leaning writings out there (written in the context of trump doing this) saying a broad-based pre-emptive pardon is invalid They would have to be read with the understanding that the reasoning is likely flawed (as we see with most TDS thought processes). There are probably a small amount of right-leaning writings of course saying the opposite. Nonetheless, broad-based pre-emptive pardons (not pre-emptive, but broad-based pre-emptive) remains unanswered it seems. ("There are several reasons to expect that a broad pre-emptive pardon would be held invalid.").
https://www.brookings.edu/articles/presidential-pardons-settled-law-unsettled-issues-and-a-downside-for-trump/#:~:text=Although%20the%20Constitution%20speaks%20of,crime%20the%20thief%20commits%20tomorrow.Then it comes to authority. Not aware of it being tested in courts. Inclination is that it would be treated like an affirmative defense after indictment. It would be a generally easy to burden to reach, with a lot of presumptions built in to the validity. Discovery could be interesting, but Courts would probably be very hesitant to undo it. Autopen versus wet signature probably wouldn't matter. Whether the "President" issued the pardon would be. Congress would have little to no say in any of it. Inclination.
Not expecting any of this to be tested or addressed except in soundbites and tweets.
The pardons were a roadmap to corruption, so its unfortunate nothing will likely happen.