Me and my wife think the food at Aulani is our least favorite part of the experience. We enjoyed Ama Ama breakfasts back when they were open but the Ulu Cafe breakie is pretty bad especially for the price, IMO. The character buffet was one step up, but not by much and considering the price one trip is maybe more than enough. The burgers at the pool are decent and my wife really enjoyed her vegetarian burger.
Monkeypod though is a great choice, especially for an early dinner. Reasonable priced appetizers during happy hour, 3-5, and 10$ tasty high quality pizzas is a real deal especially considering your in Ko Olina. Longhis at the Marriott is decent. The food is pretty tasty but having a table right on the koi pond and watching the sunset is an amazing dinner experience and it's walking distance to boot.