Solved?
This may seem brain dead, but it seems that all we had to do is make sure the correct drivers are actually installed.
Like everyone else, I went to the Microsoft Surface Book site https://www.microsoft.com/en-us/download/details.aspx?id=49497 and downloaded the November driver update. I downloaded the msi file as instructed and then rebooted. But kept experiencing problems.
Then as suggested in this thread, I downloaded the zip file. I went to device manager, and updated the drivers for the firmware (yes, in some cases the firmware is actually not automatically updated), the display adapter, the batteries, the network adapter
and Bluetooth. In each case I did not do an online search for the driver but instead "search my computer" and pointed to the drivers section of the downloaded zip. I then selected the proposed driver. As a final step, I repeated the procedure but this time
selected "Let me pick from a list of device drivers on my computer" and selected the latest version of the drivers available. Surprisingly, in some cases, not the latest driver was being used. For the display driver, I chose Intel HD 520 version 20.19.15.4316
(11/3/2015) that seemed the latest and was somehow available in my PC although version 20.19.15.4308 is the one in the zip file.
I was then prompted to reboot. On my second Surface Book, this prompted a firmware update upon reboot. In both of my Surface Books, the reboot was with no incident.
After that, all the problems have disappeared (so far). I have tested several scenarios that were crashing the video, and so far everything works.
If the solution was that simple, shame on Microsoft for not letting us know earlier.