Except that it is well known that he was not present at the time. It was just a simple matter of checking the dates on the documents against his travel schedule.
https://www.dailywire.com/news/biden-pardons-signed-autopen-on-vacation-watchdog-finds
Re: 16 - that doesn’t matter. He could have directed EOs and pardons be executed previously.
Much ado about nothing unless Biden himself says “I didn’t authorize that being signed”.
It seems like I recall hearing a few years ago that the President’s auto-pen can be used remotely(?)