If Joe Biden does what Donald McNeil suggests I will bet money a case wil go before the Supreme Court claiming a pardon cannot be issued before a conviction of a crime. I know that Ford “pardoned” Nixon, but Nixon was never actually charged with, let alone convicted of, a federal crime, and nobody presented a case before SCOTUS challenging Ford’s ability to do the pardon.
Heck, given how SCOTUS now ignores precedent, even if a prior court affired Ford’s ability to pardon Nixon, this court would simply say the prior decision was an error. My bet is that being the fundamentalists they are, SCOTUS will say that pardons only apply to convictions, despite prior practice that was been reviewed by the Court.