Great work!
Tested with a LAN connection and the IP was there after booting the image the first time and after reboot nethserver-init worked as expected. There were no errors in /var/log/messages.
Firefox refused to connect to the new server manager because of an old certificate. (it works with Chrome)
After editing the self signed certificate to renew it, it was not applied, even after logoff/logon. I needed to restart cockpit.