I just saw this here!! I’ll answer these questions for everyone, as they could help others too!
1. We move both! Start with keeping the harp fairly still and moving your head, but you’ll find your hands do start to help out and move the harmonica a bit too.
2. The nose is not used intentionally. If it is used to take in some air that’s ok as long as it is not making a loud sound.
3. Yes it would help to use that idea across the entire harmonica!
All the best,