From my understanding, only the following individuals knew about the plot on Castellano :

- John Gotti
- Franck DeCicco
- Sammy Gravano
- Joe Armone
- Robert DiBernardo
- Angelo Ruggiero
- Joe Watts

It's possible Joe N. Gallo was aware that something was going to happen to Castellano because he was asked how he would feel with a different Boss. But I don't believe, he was told directly that a hit was planned on Castellano.

In his book, Gravano also mentions that, at some point, they thought about using Joe Paruta for the hit and Paruta was willing to do it, which means he probably knew that the target was Big Paul.