I would actually add more resort time to this if possible. My family (kids aged similar to yours when we visited) did not enjoy the Dole Plantation and thought the zoo was just okay. One place they really enjoyed that isn't on your list is Hanauma Bay - though when we went it wasn't crowded (as it probably will be when you are there) and is far from Aulani.
I have to agree.
I lived on Oahu, and still never went to the zoo. It isn't really much, coming from someone who lived in St. Louis, which has one of the top, or the top, zoos in the country, and it's free.
I took, rather, dragged my family finally a few years ago to the aquarium. My daughter, the scientist, enjoyed it. Son and Husband, couldn't wait to get out.
Hanauma Bay we used to take out of town guests to, but it gets so crowded now that it is not good for the bay. Honestly, if you get up and out early, go snorkel in the lagoons and you will see all kinds of fish!
Dole to me is touristy, so I don't go anymore. Do NOT buy any crap there; you can get it cheaper at the flea market likely!
On the subject, I DO recommend an early morning at the flea market at the stadium. Go early, bring water (it gets hot). Souvenirs like homemade soaps, bath salts (use as air fresheners, I don't use them in the bath), tee shirts for $3, pareos, beach towels, dried fruits and cuttlefish (yum), nuts, etc.....
If you really want to see Waikiki (and after you get to Ko Olina, trust me you won't go back), I'd suggest a couple nights there at the beginning of your trip. We did that a couple of times (and we've been back about 10 times so far since moving away from Oahu). Just to go to Waikiki for a short trip (anything other than 14 days to me is too short, coming from the East Coast now), and the zoo, don't bother.
Also, don't bother to just go to the Dole Plantation. Stop for an hour on the way to the North Shore. Have a Dole Whip and yeah, you've seen it. It is no big deal and if you don't go, you missed pretty much nothing!
Are you hiking Diamond Head? In all my time living there and trips back from MD, never did it. You need to plan on going before traffic, which is BAD. I'd do that if you stay in Waikiki for a couple days at the start of your trip, many folks do it that way.