There are a few problems I can think of with regards to the aboriginal pact idea:
Firstly, it's a little too much "Ottawa as the Capital" and not enough "Ottawa as a city", and you might want to think of this city in terms of all the stuff that goes on away from the direct business of government. Instead of focusing on the plight of the Inuit and First nations as a whole focus on those that live in this particular area. There's the Akwesasne reservation near Cornwall, and there are natives living in Ottawa, many below the poverty line. I'd say that as a rule supernatural predators are going to strike against the most vulnerable prey, which might apply to those in the city but probably wouldn't apply to Akwesasne (too many guns). The problems at Akwesasne tend to revolve around drug-related crime and violence, or at least that's what the RCMP's publicly available information on organized crime in the area seems to say.
Ok, but you have this national organization that tried to make a deal with supernatural entities, only problem is that non-supernatural human organizations (pre-Marcone) have no status under the accords, and little capacity to enforce the pact except by force. Given that the only way to strike such a bargain would be in a negative way, by not providing protection, then possibly your national agency simply doesn't apply any force to protect reservations, maybe making a claim about lacking the mandate to enforce on Native land to justify non-interference.
I've tried looking at the role of natives in the history of Ottawa, but it gets a little confusing; the land Ottawa was built on was handed over by treaty in 1822, though there were already settlers here before that, but the group who were negotiated with, the Mississauga, never actually hunted around here. There were Algonquin here, but they were either forced out or mixed in with white squatters when development got organized.