1. I dont know they overlapped alot.
2. Luciano. Bonanno and Mangano come in a close second.
3. All 5 families, but if you are asking who had the stronger grip, then it would be the Luciano family.
4. Best connections to Capone is the Genovese family as Joe the Boss brought in Capone. Profaci family a close second as he was friendly with Tony Bello and other members from Ribera and Villabate Sicily, plus he spent some time in Chicago and was close to Tony Lombardo and Joe Scacco. Best connections to Buffalo, Bonanno family.
5. Luciano had more status, wealth and power which made him a large target for law enforcement, especially since he was flashy.

The Chin is right, Frank Garofalo replaced Angelo Caruso. John Bonventre was only a capo, you may have been thinking of Vito Bonventre who was number 2 in the family before being killed in 1930.