For a very interesting series. My retired partner and I have taken up the ukulele. While strumming and rhythm came to us fairly quickly, the bugaboo of changing chords has not.
We particularly liked this and the previous two lessons in this regard as to developing muscle memory. You are right, we had the notion that somehow we had to lift our finger(s) then automatically place two or three fingers simultaneously down in the right positions.
Your example of three people trying to go through a doorway was absolutely perfect. By walking the chord, one finger and string at a time (and practicing each in order) it made things more smooth and orderly, and I might say predictable.
You have a great way of explaining concepts that are memorable and understandable. Thanks...