That video appears to use the publicly available images, one of which is different from the image that Andy ships from BEC Technology Co. VTH is shipped with version 4.400.00000000.7.R instead of *.4.R. I can understand the temptation to install the same images as shown in the video. Thanks for the brick warning.
I managed to get Monitor VTO and Call VTO functions to work by allowing the default network to access the internet and DNS during installation. A couple of things make the whole process slow and difficult to reproduce. First, the VTH user interface has a bug where the virtual keyboard accidentally registers presses for any buttons hidden by the keyboard instead of the virtual key displayed on the screen. Second, password fields don't have an unmask option. These two things together are absolutely brutal when configuring passwords.
One-key-configuration apparently requires DNS and Internet access. The cloud based "password recovery" implementation is suspicious but I have not been successful using an entirely private network topology.
UPDATE: Access to the internet or DNS is not required. My eventual path to success was to factory reset the VTO and VTH then use VTH Quick configuration and VTH One-key Config. Simple. Good enough to deploy and then work on other wish-list items like chime integration and VoIP integration. It looks like this device delivers as advertised.