The hit was ordered and approved from Hamilton it seems, with little NYC involvement but I'm sure they had a say or blinked an eye.

Montagna wasn't a Rizzuto ally but he was gunning for top dog amongst the Sicilians, hence his close ties to the Arcuris and other Montreal sources have also told me so. He wanted to retain a Sicilian hegemony on the island and take over Rizzuto operations.

That's what most probably caused his death.