There isn't any evidence since Montagna was taken out that the Bonnano's are still influencing events in Montreal. I think Montagna pissed off a lot of people in Montreal as he tried to take the reigns. Its tough to say for sure though.
There are still a couple of groups trying to fight to take over. One of those is headed by Vito and another is headed by a jailed Calabrian gangster Giuseppe De Vito. There are probably others but recent information indicates that those are the two main ones vying for power. Alliances seem to be very fluid and change quickly.
Until someone can consolidate power and there is one ruling family I think it's difficult to gage how much influence any of the New York or Ontarion families have in Montreal.
As for who killed Nick Sr I think the evidence points to Montagna teaming with guys from Montreal and Ontario who opposed the Rizzuto's. For what it's worth most of those said to have been involved in taking out Nick Sr. are now Dead or in Jail.
