Hi dbrutus ,
first, Go through again and see that you have not missed anything.
the User Must to be local administrator on the vm's.
try to add also this REG KEY with UEM to your Vm's -
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\NonEnum]
"{DFFACDC5-679F-4156-8947-C5C76BC0B67F}"=dword:00000001
It should solve the problem.
Let me know if it helped