Does the suspicious death of Jean-Paul the First in GfatherIII have any evidence linked to Gangsterism?

Also, in terms of discussing the Mafioso golden era around the 50s and before, I don't think talking about Johnny Fontane will be of too much help.

Two options I currently see are the similarities between Roth and Meyer and their investments in Cuba, and the underworld built by the "five families" of New York.