This is very good Don. I agree we are going the same direction, maybe different paths
I once posted the question; can a neutral, equipment ground, bond, and ground electrode conductor serve other purposes?. I received all answers as definitely, no!
A neutral can carry load current, and fault current.
A ground electrode conductor can carry load, fault, and transient current. An equipment ground conductor will only see fault current.
A pipe bond will only see fault current.
The original explanation that was taught to me in technical school, is this entire list of terms is a grounding system. All are electrically connected, therefore one system. Not a combination of systems, due to them having different performance requirements.
This grounding system is also an extension of the primary supply to the distribution transformer. The No. #14 ground wire in my light circuit, has a direct electrical/mechanical connection to every home, in my area, that is supplied from the same sub-station.
My understanding of fundamental circuitry is that any conductor, regardless of its function, that is directly connected, is one system.
Most wireman have no problem with understanding the active line conductors on individual branch circuits. There appears to be some confusion in the understanding of the low side grounding system, including the neutral. By performing different functions, and applying different names, I feel this has falsely implied that each conductor is a separate system. I think this has developed, over time, by mis-applying proper terms, and the function being corrupted.
I was reminded of my original studies, and the fundamental application of theory, when I reviewed the European concept that is called the Multi-Earth Neutral (MEN) system, for grounding.
We use the same concept, only it is explained in a manner that has created a lot of unnecessary confusion.