Thanx for the reply!
I found that in project settings I can disable some of the annoying actors
So no Pawn and no HUD, we are getting closer 
Now I understand that I need PlayerController to manage camera and input. The name “PlayerController” does not fit my project, but I can live with that.
For some reason I cant remove GameState, PlayerState and Spectator, how do I do that? Or these actors also have some important roles I am not aware of?