I solved the electrical issue!  It was tempting, but I kept after this and didn't buy a new (used) harness off fleabay for ~$70 or more.

What I ended up finding, which is exactly what several people have mentioned here and on the AC forum (nowhere near as good as this one), was a fault in the harness where it goes between the tank and front of the seat/frame headed towards the front (on the left side).  I used push-pins to peel back the harness cover and check voltage, had voltage in the red/wht on the right side before it went up behind the tank but no voltage up where the harness splits off to the coil. That told me there had to be a break somewhere in between.  I kept peeling things back until I found where the red/wht was in a factory splice and it worked loose, more like just broke loose (see pics). The wiring diagram was a great help, but you can't follow these things literally. In my case, the splice here is to carry power back from this live feed back to the regulator. Why they spliced it way up here versus jumping off back by the regulator and saving 2' of wire is beyond me, but whatever.  I guess that is why I kept going back to the voltage regulator because of the voltage there but not up front, and it wasn't until I peeled things back to see the splice and understand exactly what was happening that I understood the big picture.

So, to make the repair I cut off the old bad ends of all of the wires, then got a 2" piece of matching gauge wire and joined the wires back up in a heat shrink butt crimp connectors and then sealed over all connections with an additional layer of heat shrink tubing. I left a bit of slack in this repair so the remaining wires that are solid will carry the tension of the harness and this new splice can just rest in there without the risk of getting pulled apart, etc.

On a secondary note, I also found a connection in the ignition harness that was weak by mistake (was wiggling the harness after the main repair and the dash was coming on and off) so I cut out the bad section where the harness made a very tight 180 degree bend around a bracket and all is well.

My first time chasing wires on this level and trying to make sense of a wiring diagram on my own, and I have learned a lot and am more confident the next time something like this arises.