For what it is worth, in my case the host file was provided for comparison to the others. I never commented any of these out so all of the definitions have remained active and in use throughout the events (both during the failures from last week and the current operating state).
I also reverted my DNS back to "PiHole only" and have not seen the issue recur (in the last couple of days now).
Am beginning to think that the DNS and Host config stuff is not related at all.
If this was an OS host config or DNS related issue related to these configurations, (nothing has changed on my end between the failures and the working configs), I would expect to see a failure recur but have not.
Perhaps this is simply a coincidence of timing , in which case, I have now jinxed things by my statements above and will expect another failure at any moment now ...
At any rate, I will chime in if the issue resurfaces again, but for now, all is stable for several days now with no changes on my end to account for the blip in licensing services last week.