I've installed them using
[root localhost ~]# rpm-ostree install htop cockpit-bridge cockpit-system cockpit-docker cockpit-networkmanager cockpit-ostree
[root localhost ~]# rpm-ostree ex livefs
[root localhost ~]# rpm-ostree ex livefs --replace
then run cockpit with
[root localhost ~]# sytemctl start docker
[root localhost ~]# sytemctl start sshd
[root localhost ~]# atomic install
registry.fedoraproject.org/f27/cockpit[root localhost ~]# atomic run --name cockpit
registry.fedoraproject.org/f27/cockpitcockpit has been more for managing servers I think so the needed bits aren't embedded in FAW.