Haha, you do realize that salt air helps relaxes the inflammed bronchioles right? The ships are usually prepared for little things like asthma anyways.
As for the alcohol, every Tom *edited* & Harry I know have snuck booze on board. Just but it in any non-alcoholic bottle (My friend’s used mouthwash bottles) and if they happen to see it, they can’t do anything. Some docks even have packies where you’re allowed to purchase and bring booze on board. As for Cozumel, try and get some cubans! ppl say to start haggling at 50%, but I go 60-70%. It’s worked for me.