I was able to get WPS working by first enabling the mode on my router (Netgear Orbi RBRE960) then pressing the "WPS" button on the Base 3. I had to try a couple of times, but it did take.
Relative to the unit picking a random IP address, if you know how to do DHCP Address reservations, you can always use WPS (or using AP mode to assign the name and password of your WiFi) to connect the Base 3 to your network, use your router's web interface to obtain the MAC address of your Base 3 (looks something like 00:21:7E:7B:00:1C), then assign what ever network address you like (that's on your local subnet) to that MAC address, again, using your router's web interface. After rebooting your Base 3 (power cycle), it should pick up the new network IP address.
This may sound like a lot, but it is actually less frightening than it sounds. The world of the internet is made up of a lot of these cooperating standards. This frees vendors from having to try to build (reinvent) functionality that already exists and is even fairly well documented (on your router's website).
My 2 cents...
-- Dave
