HI, I agree with the post above. I just visited Bali this past fall. I do not think this is a trip for young children. You and they would be much happier in Hawaii or the Caribbean.
I was not impressed with Bali. I guess my expectations were too high. I think in the past it was wonderful, but the population has grown tremendously in the past 10 years while the infrastructure has not kept up. If you just stay on a resort and don't travel around the island - then you avoid sitting in traffic. But if you are staying at the resort - you might as well be at a beach resort someplace closer to home.
It is 15 hours from ORD to HKG and then another 5 from there to Bali. We waited over an hour standing in line at the airport (no air-conditioning) waiting to go through customs in Bali. I can't imagine doing that with young children after flying so long. I just don't think the cost/benefit works in your situation.