Is SHARP training required at all levels?

The CinC's POTUS. So DoD policy doesn't apply to him as he's not in DoD.

I would say so, I guess for junior enlisted it's more briefs rather than training but once you are in a leadership position it should be something you know.

On that subject, you should read the book from the Female USAR MP General that was relieved of Command because of Abu Gharib in Iraq? Read like General Sanchez crossed the line a few times, would be interested if that was ever brought up in SHARP or if the Army considers that a taboo subject due to rank.