Would Germany's NSDAP be considered fascist if Hitler never allied with Mussolini? Does the term fascism really fit as an umbrella term for all those right-wing and third-position parties, or is there too much of an ideological difference between them to fit under a single umbrella term? Did 'the Fatherland front' of Austria, Hitlerism, Strasserism, and Italian fascism really fit together?
In the Hearts of Iron series, the world is divided into 3 ideologies (plus a "neutral" ideology), where fascism is broadly defined (Japan is included as fascist), and it seems to be the way people use the term mostly, as a broad term that doesn't go into specifics.
But It seems to me that in an alternate reality were the 30s had gone in a different direction there could have been enough of a divide for Hitlerism to not be considered at all the same thing as Italian fascism, and for the two to have been serious rivals. Same thing with right-wing catholic groups. And Strasserism being considered communists, etc.