According to Gianni Russo (Carlo in The Godfather) in the Godfather Legacy documentary, Vito is mostly based on Carlo Gambino. His control over judges and politicians is based on Frank Costello, and having an olive oil company is based on Joe Profaci.
Yes. And, wanting his son to succeed him was based on Joe Bonanno.
Puzo put all those Dons in Vito's character. I think he was most like Costello, who was called "The Prime Minister of the Underworld" because of his gambling-based position and his political clout. He also eschewed drugs, as did Vito.
