OK - Issue #3 still persists. I have attached pictures of what it looks like.
Here's what it looked like when the monitor was resumed from sleep. NUC had been idle for about 1.5 hours, with my Gmail open in a Chrome browser. No other apps open. I had no mouse/cursor, no background, no window border on Chrome, no taskbar. By the way, the NUC is set to never go to sleep - this is just the power settings on the monitor itself turning the monitor off after 10 minutes.
I unplugged the monitor's HDMI cable from the NUC, then re-plugged it in. This is how it came back:
I'm sure the resizing and moving of the Chrome window is just an artifact of hot unplugging the monitor. But you can see that the desktop has been restored and I have a mouse again. No other side-effects have been noticed. I can resume working once I do the cable unplug/replug operation.
Thanks