Also I have questions about the sheep-producing capabilities of Canada and Nova Scotia. What exactly is the source of the "abundant pastures"? I was under the impression that, at the time of contact, the area was pretty heavily forested. Certainly there would be some grassy areas, but they would probably mostly be marshland, which is not quite as good for herds of animals as firm-surface grassland would be.
The settlers could be clearing land for pasture, but the amount of land you'd have to clear to support a flock of sheep would be too much for a single shepherd to do on his own..... Clearing land with slash-and-burn farming, and then switching to pasture once the soil loses fertility seems more feasible, but would be unsustainable and was not something English or Scottish settlers would have experience with.
Or, what seems more likely in my mind is that the "abundant pasture" is actually abandoned farmland. In the upper St Lawrence Valley and lower Great Lakes, thr Native people at the time of Cartier were farmers and had cleared fairly extensive areas of land. By the time of Champlain, these people were gone, but I'm not sure how long it took for the farms to get reforested...
One other interesting point I'd like to make about sheep is that you'd probably see the Iroquois (or other Natives in the areas depending on the alliance systems) capture herds of sheep in their raids, and in doing so learn how to take care of them. Sheep herding (and using their wool for cloth) is actually something that would be a great economic benefit to all the agrocultural Natives of the eastern woodlands as they were dependent on hides for their clothing, and often times had to migrate when hunting grounds were depleted. This could allow the transformation of some of those hunting grounds into pasture and could create a transformation of Native culture as great as that caused by the introduction of the horse farther West.