Hallelujah!
All is back to normal and map v9.65 loaded and working! (Without calling CS of course!)
All I did was install a small Europe map, which worked w/o problems, then MyHome showed ~4000mb free, which should have been enough to squeeze in the updated N.A. map. Which, 36 mins later was also installed flawlessly. For the first time in all this process my "free space" showing matched in both MyDrive connect, and the Community Content screen. This was something like 79kb, so I then uninstalled the Europe Map to free up space, as I don't need it anyway, and I have tons of free space back too! (I play around with custom POI files a lot)
From what happened from the very beginning, throughout the problems and solutions I have a theory: The new map is 3920mb. At the time, I think MyDrive was reporting about 3600mb free. I assumed that MyDrive was smart enough to remove the old map, thus freeing room, and only then it would install the update. Apparently it is not that smart the errors started. (I should have known).
So, I thought I'd uninstall the old N.A. map, then install the update. Nope, that is how I got stuck in the "No Maps Found" Loop Of Hell. At that point MyDrive wouldn't install the update, because MyDrive still reported not enough space was available, even though there was supposedly no maps installed at all! (I think this is part of the flaw, the maps are uninstalled, but not "cleanly".)
So, apparently installing an old unused Europe map refreshed the space available which was enough to also install the new 9.65.
For what its worth, hope this helps someone else get out of this jam!