As long as it's a federal court holding them in contempt, Trump can just pardon them.
Criminal contempt has this problem, but civil contempt is not pardonable, because there is no crime to pardon.
Judge Boasberg is trying to proceed with criminal contempt on the "turn the planes around" order. Whatever happens there, it is unlikely to end in convictions that stick.
Judge Xinis is proceeding towards civil contempt. If she finds someone in willful contempt, she can imprison them until they choose to comply. And the evidence standard in civil contempt is "clear and convincing," not "beyond a reasonable doubt."
Harvard has a serious law school, but they got some big names in private practice to rep on this litigation. That's probably a good move for them.