Nice shots, I like the first 2 shots.
I'll bring CF and SD cards and a backup external SSD drive. Those are a given.
I'll bring my standard zoom and 100-400 zoom. Add to those, my 100mm macro, just in case.
But, I'm afraid there would not be a lot of shooting, since we're only staying in one place per island. And my brother does not move very easily.
-r
The first two are more carefully PP.
Take the macro - even if you don't move from the resort (if you still aim at that one here, on Oahu) you will have opportunity to shoot macro. And you always can rent a car to visit other parts of the island. One very good place to shoot flora is a botanical garden on the North shore. It's the only bot. garden where you have to pay but it's a gem! And for 10$ you can rent a "taxi" (small carts) to move across the garden - it's rather big.