Okay so here's what I ended up finding out after giving up on the unit which was a home addition unit. I ordered a Windows 10 Pro Surface Pro 7 for business directly from Microsoft, connected it to dock v1, and tested with up to 4 monitors plus surface screen. I repeated the following test for each added monitor starting with no external monitor.
USBc monitor connection tests resulted as described in the other post... 2 usbc monitors seems to not be supported. But no blue screen. Removing the pluggable, still doesn't allow for the USBc port to be used, registered but doesn't receive signal. I hypothesize that at least one more plugiable could be added on the basis that each one is another graphics card.
Each related updated increased stability and in one case an additional monitor. In the end, with all updates upto win 10 pro v1909. It is capable of 3 external monitors using the dock v1, 2 x mini display ports, Plugables 1 x USB 3.1 to hdmi adapter, the surface screen. The portable adapter works because it's adding an additional graphics device.
The on board gpu/chipset will not support more than 2 external plus surface screen. The Plugable adapter integrates via a new registered graphic device. However using the USB-c side jack allows a 4th monitor to be registered but it will not get signal.
The repeatable test I used was a graphics bench mark. I was able to run one instance per monitor. The blue screen would occur whenever these were shutdown. So it was trying to clean up memory when it would BSOD. On the business unit, when shutting these down, I would have to close it twice before they would shutdown after stability update, they would shut down after showing the credits on a 5 seconds delay.
So on the new unit I wasn't able to repro the issue.
Either their is a patch on the business unit and not on the home Edition or there is a memory or controller hardware issue on these units. I am leaning toward the latter.