One of the many flaws in The Godfather Returns is that Winegardner decided to make his book a direct sequel of the book, which meant that Stracci and Cuneo are still alive. Even though they're not main players in the new book, they're mentioned, and that takes away from the continuity from the movies to the new book.

Winegardner should have just not mentioned. That way they could have either been dead or just out of the picture.