I was thinking Stefano Sollecito, but it's been a while since I read the book and don't remember the clean record part (not saying anyone is lying, I'm saying my memory sucks....lol).
Vito and Leonardo was under investigation before as I think both were on wiretaps. So he had some prior knowledge beforehand, but whether the whole "family" knew he was in on things or not who knows?
As for the Loreto stuff, I quit trying to figure that stuff out. It seemed out of the gate if you were not allowed to have your funeral there it meant you were out of favor but know it seems they will serve anyone, friend or foe.