I just wanted to follow up on my last post. I did not see the reply from Joshua_H at the time so I apologize for that, the automatic 20 day window closed. At the time, I would have been using Fedora, probably 27.
What I wanted to mention is that I made a small patch for systemd that enables the Pro8 to act the same way as the UD-160 models and submitted it to be merged to main.(see link below) Presumably, the next version of systemd (The next release should be 245) will contain this support out of the box on any Linux distribution that contains systemd. Being as all I did was make sure the new device IDs are properly recognized, this is using the same code paths that Plugable created some years ago for multiseat on the UD 160.
Currently, my test computer has Ubuntu 18.04. When I plug in the Pro8 what I see is that a new/second login screen automatically comes up as expected without any manual configuration.