The latest version of Unleashed, version 18.104.22.168.64 is what your network upgrade will install, so you should start with the latest/greatest. The "GA" acronym stands for General Availability, or our first release (first 2 digits), which are followed by Refresh(s), or the next MR (Maintenance Release).
For an Unleashed network to setup correctly (any version), the APs look for a local DHCP server and def-gw. Can you try setting up in the actual location/network you plan to use the APs? When your network is setup, any version, and all APs recognized, you can do the Admin upgrade if/when there's Internet access.