Lived on Oahu for 3 years, agree NO luau. It's mediocre food, LONG show (if you do Paradise Cove, done it a few times). I got so tired, and we lived there, but in Kailua which with no traffic is a good hour away. Show is just "meh" and just drags on and on.
Shop Costco! Daily if necessary! Make your own drinks, get a little soft sided cooler (got my favorite ever at
Walmart in Kapolei) to bring to the pool or beach (yes, the "official" rule is no drinks on the beach - never seen that enforced long as you're discreet).
If we eat out, it's lunch at a local spot. If you like sushi, Sushi Bay in Kapolei is super generous with portions and super ono! Cheap too. It's worth the wait.
Dinner for us is always in. Tired, hungry, kids don't want to go out. Grill or get something easy from Costco! I often get chicken and Yoshida's sauce there, marinate it a couple days and have chicken teri with rice! We had a party of 12 a couple years ago, so did a huge batch and shared.
Now is the time to check out clearance aisles at Walmart and Target for pool floaties. Nice to have your pool floaty in the ocean, and leave it for someone else when you leave! I usually get a good one for like 3 dollars! Not sure if Aulani has pumps but the Marriott has two for free to blow them up.
I agree to pack a suitcase of snacks. I used to coupon a lot, so one trip had one full of pantry items. I always bring things like plastic storage containers, Reynolds Wrap, spices, pancake mix, etc.... Except the one trip when we just brought carry on bags (for two weeks) and bought it all at Target.