You pose some very interesting questions.
For anyone who has asthma and would like to keep a medicine stash, I finally got a straight answer from a pharmacist yesterday.
The albuterol vials for use in nebulizers (eBay has lots of battery powered nebulizers, I’m currently saving for one.) are marked with an expiration date on their package.
The pharm said it is at good, full strength fully 7 months after that date. She then told me that Albuterol gets weaker, not stronger. So in an emergency situation, one could just nebulize perhaps every 3 hours instead of 4 beginning at around 9 months AFTER the expiry date on the package.