SAS-A321,
I was at Moncton for my PPL. For the Visa, I'm not entirely sure how that would work. But I know there are a few non-Canadians working as instructors in Moncton. So I'd venture a guess that there are reasonable grounds to work there.
As for FAA v. Canadian, they're pretty well on par with one another, but I have been told that the Canadian license is a bit better in terms of the training.
Snowy conditions don't necessarily ground aircraft, but while doing my PPL at Moncton there was no flying if snow was falling because the training aircraft were not certified for operation in icing conditions. Exceptionally cold days (in the order of minus 20 degrees C or so) would ground the aircraft as well until the temperature rises a bit.
Canada as whole is a great place to live, and Moncton is no exception to that. It's a great little city with a lot to offer. There's excellent shopping, the people are great and the nightlife is surprisingly good. The quality of life is great as well. Living expenses are quite low and the public transport is also very good given Moncton's size. Overall it's a fantastic place. If you do decide to make a home for yourself there, you won't be disappointed.
Best of luck!
