Hi Craig!
Sorry for a very late reply but I actually did give up back in March (changed work right after that = did not drive me further for my needs).
Just picked this subject up again to try it out and it finally worked!
Yes, GoPro VR Player 3 was at least the solution for MacOS to get a spherical presentation of the feed + installed the THETA RTSP STREAMING plugin!
And followed the guide how to get hold of the IP name of the Z1.
RTSP always give quite a delay for realtime but for the purpose to demonstrate something without care about lip syncing this is great.
Still a hardwired solution with no latency would be the best solution but this still proofs it works for MacOS! (If there is a way to get hold of the live feed from the camera and bring that one into GoPro VR Player 3 would be great.)
Thanks for the never-ending support! 
Just wanted to reconnect not to be that dude that just stops give thread feedback suddenly.
Mission accomplished!