When I went in 2014 they did. However, when I called Aulani to confirm whether or not they would be having fireworks, they could never tell me definitely if they would. Apparently, the area timeshares(Marriott, Aulani, etc.) each pay a share for the fireworks to happen. The fireworks were right over the Aulani lagoon at 8 or 8:30pm. They were great and there was a soundtrack that accompanied them. When you check-in, ask if they are having them. That's when I officially found out that they were a go.
On another note, if you want a chair by the pool make sure you get up early to get one. I usually reserved one(put my towel in it) when I went down to get breakfast around 8am, but a lot of them were taken by then. It was crazy when I was there from the 4th-8th last year. After about July 6th it calmed down but there were sooooo many people.