Seriously SP I have thought long and hard about this trip you are undertaking for a very long time. Mac, TB, Locky and Tux are recent returners from my re-collection - lets hope they chip in shortly.
In no particular order here are a few must things that I will be doing - from someone who has yet to go there but will be soonish I hope
1. Wait for a smallish (by their standards) day with light winds at this time of the year and go north and surf Pipe. Even if its just for the paddle out experience. Even if it takes 5 hours to get a wave. You have to take one no matter what. As a surfer you owe it yourself. Imagine the tall tales when you return. Maybe high a local fella to shoot you. If you get a couple then take on Backdoor - head straight to the beach afterwards - don't paddle back out through the guts - save your energy and do the paddle round from Pipe.
2. Find out where JOB is hanging - especially if there is some swell and go watch him and his mates do stupid **** in waves that look too big to me to be playing silly buggers with.
www.instagram.com/whoisjob/ for inspiration
3. USS Arizona - 1,300 free tickets given out to first 1,300 - so go early. Not a war person myself but this was a significant world event so worth spending some time checking it out whilst you are there.
4. Feeling rich - jump a plane / helicopter over to see the lava hitting the water on the big island. Or head up for sunset to see Kilauea and all the cool lava - its the most active volcano on the island - no live volcanoes in Oz - so good opportunity to see one in action. Might be tricky with the youngster in tow
5. Walk up Diamond Head for the view
6. Get dropped in on / drop in other surf craft / ride some weird craft that you would not normally get the chance to do
7. Surf Ala Moana Bowl if you get the chance - that place looks / sounds amazing
8. Eat at one of those amazing food joints on the beach front that everyone raves about - massive tasty burgers
9. Do some high quality viewing - try not to get busted
10. Give the baby some junior sleeping pills equivalent and pretend you are on the honey moon for a few nights
11. Go for a roadie around the Kam Highway. Check out the big time breaks - Machaha, have a bodysurf in the Waimea shore break. Buy an Eddie would go T-shirt (if so get me one too - mine is 6 years old and needs replacing - XL please - Any dark colour cool with me

). Call in at the infamous Foodland supermarket and try spot a pro or two. See what all the fuss is about.
12. Buy a good quality gun (probably second hand as end of winter now) - mine will be a smaller version of Tux's as I do not have the balls to ever ride it in the conditions it was made for.
Anyway thats a few to get you going. I am massively jealous - enjoy yourself !