If you create a host with API then it is good to also trigger a service discovery over the API. If the host is created inside the GUI then the same why not trigger directly a service discovery over the GUI.
From command line the correct command is “cmk -II hostname” or “cmk -I hostname” for a discovery.
If i see the screenshots of your hosts the i would say again. These are no normal configured hosts. What is the host check command for these hosts?. Every host without services is shown as down why?
If a host is down then also no automatic service discovery will run.