Thinking about layers
I oftentimes use the fore-ground layer to frame my views. Objects in this layer are carefully detailed and act as a “curtain” for the scene beyond.
Objects in the back-ground layer are usually sketched as outline images with very little details, e.g. the skyline of a city or trees in the distance.
The middle-ground is reserved for the “focus” of the composition. It is a “3 dimension” layer that tells the story and set the scale of the sketch. All objects within this “layer” are governed by the horizon and vanishing points.
Sketchingjourney's Blog 
I like your illustrated rational analysis; the colors definitely enhance the readability of what you want to tell.
It’s a bit simplistic since all layers are in fact 3D layers, and they are interrelated among themselves. I like to keep the focus of the story of my sketch in the middle-ground layer, and usually in this zone the third dimension and the vanishing points have major roles.