I thought all dons are referred to by their first name, maybe not diminutive, like Don Toto' instead of Don Salvatore, but never by surname. The only examples where "don" precedes the surname are the Godfather movies.

By the way, do you think the Madison don Carlo Caputo could be called Hitler Kaputo in his face?

Also, Giovanni Brusca from Sicily: if called "Don Giovanni", that's an euphemism for "womanizer" in Italian.