Fauci is an easy one. He’s testified before. Rand Paul has accused him of committing perjury, and it’s pretty clear he did. So drag Fauci in front of congress and ask him for truthful testimony, and let him know perjury from here on out will obviously land him in jail.
Then the Trump admin should use everything he says against him in court while disregarding these bullshit pardons.
That does open the door to the possibility these criminals would still exercise their 5th amendment rights until SCOTUS sorts out the pardon issue (which I fear isn’t going to be challenged, because Trump is going to want that power too, now that Biden admin set the precedent).