What (winter) temperature is this rated for? Is it suitable for Maine winters?

Carhartt does not temperature rate any of its garments because everyone has a different threshold on what they consider to be cold. This jacket is designed to be worn during the winter. However, it could require additional layering by some people.

is it possible to exchange my jacket which made in Mexico, for the one made in India? The India made jacket has a better blanket lining.

I much prefer the made in Mexico Jackets. Took me 3 made in India Jackets to find one that the stitching wasn’t messed up. Be careful what you ask for.

There are two snaps at each sleeve. One snap setting gives me a lot of room at my wrist, the other setting is so tight. Is this normal for this jacket

On my jacket, the first snap does have a loose fit around my wrist (which is how I wear it with gloves and what I prefer). The second snap has a snug fit, but I wouldn't say it's tight. The fitment of the snaps on your jacket might be due to a variation in the manufacturing process of each jacket, but that's just my guess. Hope that helps.