We took five month old twins, then returned with our then-15 month old twins and again when they turned four.
The only time they got jetlagged was the time they were four.
Even then, we got to enjoy a lot of sunrises and just all went to bed early. After the first half of the trip we gave up "switching" them and just stayed largely on the early end of east coast time.
They loved the aquarium at Waikiki (running around the place pointing at all the ISH - for some reason they never put the F on the word) and the beach. My favorite picture ever is one of my girls speed-crawling away from us and into the Pacific Ocean. We ran to get her after taking the picture, of course
They did NOT like the luau we tried to go to when they were 5 months (at Hale Koa), so we didn't even try it when they were 15 months. It was WAY too loud. They loved it at four, though. Decide on your own about the luau depending on how your child does with loud noises.
I'd avoid taking your son to the USS Arizona memorial until he's older. It's just not a good place for little kids to be running around. It would likely destroy the mood.
Go to the Aloha Stadium swap meet - we still have the leis we got for our girls there. Artificial, but they look good. And we still have books we bought at the Exchange and the ABC Stores that are specifically about Hawaii. In fact, before you go, get a hold of a copy of Geckos Surf. There's about five books in the board book series, and they're really cute. OH - and if you or your family have access to the military exchanges, do your souvenir (and Aloha wear) shopping there. Especially at Pearl.
Now I've told the girls they have to figure out how to use a snorkel before we go back (probably in two or three years). I want to go back to Hanauma Bay. Kids can go there and looked like they were having fun, but I didn't want to go back before the kids are able to participate. Taking turns on shore didn't seem like fun, but if you can get family members to help too it might work for you.