Sinatra you have every right to brag As for De Vito I agree, once I heard it was poisoning I thought Vito had something to do with it. I think this kind of confirms it as I imagine Boucher has a lot of sway in prison.
You're right in that Leonardo/Stefano is not listed in the murder plot so far but I seriously doubt Boucher would go after Desjardins unless he had their backing. We have to remember the HA's and the Rizzuto's have always had a history together ever since the war between them and the Rock Machine was stopped. I just can't see them going after Desjardins "alone". It's also been thought that them and the gangs have been hitters for the Rizzuto's as well so it's plausible.
Sinatra have you ever seen the Rizzuto tapes? Montreal Gazette has them online where Vito and Leonardo was on tape talking but it wasn't anything incriminating though. Surely they had Cavaliere's office tapped.
As for lawyer/client privilege, yes they have it in Canada. I think that is the main reason Leonardo became a lawyer to get that right and to keep the RCMP off of them. I know police can tap a lawyer's office, but I think they have to prove they are not meeting for a consult or something. I've seen it done in the states before but I vaguely remember how it was done.