Great idea on the SPF clothing...the sun is very different there and babies need hardly any exposure to burn - even if they are in the shade under an umbrella on the beach or near the pool, the reflection of the water or sand can cause burns too without adequate protection. My pediatrician loves Blue Lizard sunscreen the best for babies because it's chemical free.
I've personally always liked the Banana Boat tear-free SPF 50. We've never had any problems with that one, it gives great coverage. However, I wouldn't say it's 100% tear-free, if my son accidentally rubs some in his eye when I'm applying it, it will get red and tear up. Otherwise for regular use (when he doesn't rub a dollop of it right into his eye) it does seem much more gentle on the eyes than say Water Babies (the WORST on the eyes!).
Yes, use bottled water for his formula, I don't see how you would have much of a choice there. Nursery water will cost too much to fly with because it's heavy. Also you could use the Gerber plastic baby food containers (they sell a large variety at Target), or just ship his glass bottled food there ahead of time. The only issue with shipping would be if the hotel didn't receive or lost his food or something. I would personally just bring my own. Gerber makes organic varities in the plastic containers. Maybe not necessarily the brand you want to stick with forever, but for the trip it would work great.
Have fun!