Will freezing affect long term storage of dry or canned goods?

Jars should have 1” head space between liquid and lid, and I would stick with canning jars, not reused jars from store. Dry goods with oils such as nuts, cornmeal or whole wheat flour can benefit from freezing because the oils will stale slower. Hot weather will speed it up. Jars might be good option for those, too, as you don’t want to attract creatures.

Cans could freeze and split open. I would be leery of any jars, no matter what kind, that could freeze and break. Dry goods should be okay.

Yes. If freezing breaks the glass or cracks the can, then the food may well be spoiled.

If you’re going to do bulk storage, do it in the basement, not the garage.

I suppose thawing might breaking the seal on a jar. Generally when food is frozen in jars it is intended to be eaten shortly after thawing. If in US, your county extension agent would have food safety resources.

We don’t have freezing here, but we store hundreds of canned goods in our garage on shelving near the house door which is the warmest part of the garage. We have done this for several years.

If you have dehydrated or freeze-dried foods, freezing will not impact it. Jars and cans can be adversely impacted if the liquids in the container freeze. Just like a frozen water pipe, they can crack open.

One suggestion for dried goods (flour, grains, etc) is to get some mylar bags and some oxygen getters and transfer the product to these new containers. Put your dried goods into the mylar bag, drop in an oxygen getter, and seal the bag (a curling iron does a great job for this).