Sounds like a very comprehensive kit. I don't know practical it would be to carry all that around, all the time.

It doesn't sound like you need any prescription meds, but I'd add that to the list since it doesn't seem to fall under your "common meds" term.

For your drink mix, you might consider getting an electrolyte mix instead of something like Kool-aid, in case you're ill and need to stay hydrated.

I don't know if I'd bother with the Datrex bars. If you're going to go to the trouble of packing normal food, I'd much rather munch on that, unless you actually LIKE Daterex bars. A lot of folks don't have healthy diets and they suffer blood sugar crashes if they don't eat sugar every few hours and become lightheaded or ravenous. Those are the types that really need to pack some snacks, since the recent cruise ship incidents demonstrated that food service can be painfully slow during some of these incidents, like when main power is knocked out. Otherwise, I would classify food as more of a comfort item in such a kit.

Under documents, I would put aside a credit card just for the kit, separate from whatever is in your wallet. Just some redundancy in case you don't have your wallet or your kit with you. You're going to the Caribbean, not behind enemy lines, so using plastic should not be an issue for important things like buying your own plane tickets home in case the cruise ship line leaves you in the lurch, so to speak. Also pen and notepad, maybe with waterproof paper.

Personally, for a cruise ship emergency kit that is small enough to comfortably keep on me all the time, I think I would stick with the most urgent basics. A long-lasting, waterproof light, preferably with some spare batteries. A headlamp would be most practical but a handheld light is fine. You don't need much light in the pitch dark hallways of a cruise ship without power. If you're a situation with dense smoke, I'm not sure how much more useful a bigger, more powerful light will be than your headlamp.

Then smoke protection. The Safe Escape is an excellent choice, but on the bulky side. The Xcaper mask would be a more compact option that still provides good respiratory protection against stuff like carbon monoxide. Enough to get you to safety.

Maybe a whistle for good measure. That would be my absolute minimum, I think, for a true emergency kit.