also - even though the pedestrian has the obligation to move over - a friendly thanks! or thank you! helps all cyclists in the long-run.

This again depends on the jurisdiction and kind of path you're on. Where I grew up, if it's not separated into bicyclist & pedestrian lanes, bikes yield to pedestrians.

On US forest trails, the general rule is bikes yield to pedestrians and everyone yields to horses.

(Obviously pedestrians walking in bicycle lanes are doing it wrong.)

Yep, a wave helps as well.