Well, let's take a look at the aftermath of GF III:
1) The Pope (John Paul I/ Lamberto) is dead, literally hours after approving the Immobliare deal. This would be absolutely huge worldwide news.
2) Archbishop Gilday is dead; there aren't that many archbishops in New York, so this would be pretty big news;
3) Keinzig (Swiss Banker Fuck
) , the director of the Vatican Bank, is dead;
4) Lucchesi, known to the public as one of the directors of Immobliare in Europe, is dead;
5) Altobello, who would be known at least publicly as a Mafia don, is dead;
6) and Mary Corleone, announced weeks earlier as the chairperson of the Corleone Foundation, is dead, shot at the same opera house where Altobello keels over dead.
Plus the assassin Mosca, the "twins," and a couple other Corleone bodyguards are dead at the opera house. There's no way you can remove a half-dozen bodies from a crowded opera house without a huge commotion.
As Lamberto quite accurately predicted, there would be a huge scandal.
However, the Church could really not afford for the full details of the scandal to come out, since that would reveal the full depth of the corruption of the Vatican Bank, the involvement of an archbishop, and the murder of the Pope, which would throw the Church into chaos from top to bottom.
So my guess is the Church, and the Italian government, would go to some lengths to cover up the details of the scandal, and to some extent to scrub Michael clean publicly, and paint him and his family as "victims."
The new pope (Paul John I ??) would probably go to some lengths to uphold the decisions of Lamberto (as the real-life John Paul II did for the real-life John Paul I).
Interestingly, the character of Lamberto/John Paul I in the movie seemed to be based more on the real-life JP II: a friendly, powerfully-built man, multi-lingual, relatively younger in terms of a Pope, a man looking to "clean house" at the Vatican.
The real-life John Paul I seemed to be more similar to Gilday: a thin, bespectacled, fidgety, frail-looking, chain-smoker.
