I like this theory as well, I can't remember where i read it, it might have been Mafia Inc where they stated that very scenario. Rizzuto Jr. being killed because of a separate dispute, having nothing to do with current war.
In Mafia Inc. it is stated that law enforcement is linking the murder of Nick Jr. to the murder of Frederico Del Peschio and that it hasn't anything to do with the other murders. Other mafiosi were probably eager to see how the Rizzutos would respond. That response came a few months later when Joseph Ducarme was nearly killed. I think this could have been the last act of the Rizzuto family.
"It was between the brothers Kay -- I had nothing to do with it."
