The "god" of the alt-right is Richard Spencer. Granted the definition of alt-right has shifted around, but by the current prevailing standard among those who adopt the label and used to do so, I think it is strictly an ethnonationalist movement. Unless you're going to cite rumors about Bannon, I'd say Breitbart doesn't quite qualify. Again, forgetting anything Bannon once said about it being the platform of the alt-right, and going by current running definitions. Breitbart would probably be considered "alt-light".