It's the same with a low-meat diet since so many restaurants don't offer food without meat - you end up not eating out as much or selecting healthier items.
[0] https://www150.statcan.gc.ca/n1/pub/82-003-x/2008001/article...
However your statistics there have way too many confounding factors to attribute anything substantial to the native diet. Infant mortality rates historically and remain (comparatively) very high. Alcoholism is rampant among Canadian indigenous people. Even among peoples who have similar diets such as e.g. Metis, Inuit and First Nations peoples, life expectancy is significantly different (this is before even getting into a comparison with other meat-eating cultures in the world).
There is virtually no signal here to determine the healthiness of an Inuit-style diet either way.