Cedilot has been proposing that theory for years. Back in 2010 he said the same, while we now know that the take-over came from groups within Montreal. I don't believe the Montreal Mafia, which comprises hundreds of associates, will allow Ontario to rule over them. The arguments that are now made against Bonanno influence also apply for Ontario.
The Calabrians are only interested in drug and arms trafficking, the HA would be the best partner. They are not interested in controlling the Montreal streets I would think.
I understand what your saying they will not have a big presence in the streets, they don't have to. But if you control the drugs you more or less control the rest.
I think they would leave the local stuff to the Hells Angels, they have the men, those who survived the biker war and newcomers.