1) Yes it is true.
2) Malavita hit it on the head, Aurello was not scared nor stupid. He knew the winds had changed and it was a smell he did not like. He already had Gravano as his acting Capo, and had been grooming him, to where at that point, it was a good time to retire and let Sammy take over the reigns.
3) Toddo died after Gravano cooperated, but none of that hurt his crew, which means it was part of the deal Gravano had made with the FBI.
4) Salvatore Aurello was powerful in his prime. He came up under Tommy Rava crew, he was close to many members in that crew, such as Neil Dellacroce, Tony Rizzo, Mike Ciazzo, and Petey Pumps. He went with Rizzo when the Rava Crew was split, and became Capo of the crew when Petey Pumps died, after that he was close to Gambino and Castellano. Over the years Aurello was respected by Gambino, Castellano, Dellacroce, Fialla, Joe N. Gallo, and many more members in the family, where if there was a problem, it did not last long. He had a lot of pull, but also had alot of respect from other families which made him a good Capo, and biggest trait he had, was his fairness among everyone.