It'll be good for the younger kids. The older ones will have fun in bigger waves elsewhere. There's plenty to see and do on Oahu but from your corner of Oahu I'd mostly stick to exploring west side beaches and hanging at the resort. A couple other outings will be fine and if you want to spend a day on the North Shore that is the best part of the island, but trying to run all over the place to see and do stuff will kind of miss the point of being in Hawaii. The kids will just remember the beach and hotel anyway.