@Hunter_D
I have copied your list, so my comments follow, for Namibia:
My comments are based on what I have seen, in free range and high fence.
Kudu - high fence and free range
Gemsbok - high fence - and free range
Red Hartabest - free range
Impala - high fence
Springbok - high fence
Blesbok - high fence
Wildebeest - black wildebeest is south african animal, in Namibia high fence.
Zebra - high fence and free range
Waterbuck - high fence and free range
Nyalya - Nyala is south african animal, in Namibia, only high fence
Sable, very valuable animal (up to 6k USD, introduced = farmers investment) , in Namibia, will be high fenced in central farm land. For free range Sable, need to go to Zambia, for example
To add few:
Leopard - jumps over any fence, consider free range
Warthog, digs under any fence, consider free range
Baboon - free range
Jackal - free range
During travel from Windhoek international airport, I have seen many animals along the road to the area Otjozondjupe (dozens of them).
Those are certainly free ranging animals:
Kudu, red hartebeest, warthog, waterbuck, baboon, oryx.
This should be some indicatation of what to look for.
My personal list to hunt free range animals, out of fence, in agreement with outfitter, if the aninlas are availabel in his area, is:
Kudu, Oryx, red hartebeest, warthog, jackal, baboon, Zebra (preferably Hartman Zebra).