Thanks for the reply. To be honest, I'd already tried what you suggested. I finally have them mostly working like they should.
For the main unit to "see" the additional unit I had to use the wireless connection option and I also had to change the IP address of the additional unit. Initially the IP on the additional unit is the same as the main unit, and as long as they were the same I never got the additional unit added.
The first additional received the config info and started functioning. The main unit got stuck at the adding unit final screen and finally errored out. So while the additional is functioning - the main unit and ios app don't see it as a part of the system.
The second additional added successfully and is working and seen in the ios app.
I can only say that there is something going when attempting to set them up after resetting to factory. Had I left well enough alone I wouldn't have gone through all of this, but hopefully it helps someone else out.