No. of Recommendations: 2
Given Trump's history, I will not be surprised if he chooses to ignore that law and issue a pardon, forcing the issue into the courts. Once in the courts, he will not stop with appeals until he gets a favorable ruling or is denied by the USSC.
He wouldn't be a party to any appeals.
He could issue a pardon to Bannon, and Bannon could raise it as a putative defense to a New York state prosecution - but there's no way any state court judge would agree with him. He could then try to get the federal courts to intercede, but it's ridiculously unlikely that the SCOTUS would side with Bannon. The Constitution is so unambiguous that the Pardon power applies only to federal crimes ("The President ... shall have Power to grant Reprieves and Pardons for Offenses against the United States, except in Cases of impeachment.") that it's implausible that the Court would side with Bannon.
