(1) Yes. Despite all the claims from canister stove makers (especially Snow Peak) about not mixing brands, all canisters and stoves with the standard Lindal valve are interchangeable.

If nobody here can answer #2, you might try the Whiteblaze forum. I know that at some very small resupply stops in the Pacific Northwest, they are hard to find. If there's a gas station, you can almost always find HEET, one reason why alcohol stoves are more popular with thru-hikers.