Thanks for your helpful response.
I guess I neglected to mention that I have also booted in Safe mode, with no difference, the MacBook pro still hangs on shutdown with only outline cursor showing on screen.
I would love to get some useful information out of activity monitor as I think you are correct that some process is hanging. Unfortunately when you do a shutdown, the activity monitor is stopped without showing any useful info, or at least I have not seen any.
Interesting note though, when I do a shutdown and it hangs with just a cursor showing, I can still telnet into the device from another computer. I have tried to see what is hanging but can't identify the guilty process that is pausing the shutdown. I can still execute shutdown -r now to boot the machine, but this was not helpful when trying to do the last macOS update as the update would fail to initiate during the resulting boot. I finally had to install the update with opt/cmd/R, and still the hanging on shutdown has persisted, even with the 10.13.6 update.
I have not as yet erased the entire volume and installed macOS from scratch.....but I am thinking about it.