What should Whiplash do about Fallwellon's directions considering, and what he knows about Fallwellon's feelings which may result in a civil rights violation?

Nothing, just complete it and submit it to Fallwellon.

His feelings are irrelevant. What is relevant is whether based on state law, the company is allowed to terminate a person due to their employee's off duty behavior.

Advise Fallwellon that terminating an excellent employee like Cruize could result in legal issues; he has done nothing wrong; he was not at work, and there may be other's who have acted in similar ways that were not let go$.$

Advise Cruize of Fallwellon's intentions and how to counteract them.

He should complete the paperwork, put on Fallwellon's desk and advise Cruize that he is going to be fired and why.