Here is the response that I received from Disney regarding the 4th of July:
Aloha Moe,
Believe it or not, this is a very popular question around this time. Our resort opened at the end of last August, so this will be our first 4th of July in operation. At this time, the resort has not yet made known any plans for Independence Day celebrations. However, I did a little research and found the following, which may be helpful to you:
Firecrackers are a strong cultural tradition in Hawaii, especially among Hawaii's Chinese American community.
According to a travel site: On the island of Oahu there is a public aerial fireworks show every Friday night in Waikiki, there are fireworks shows on New Year's Eve, and there are usually fourth of July fireworks displays in Honolulu, at Maunalua Bay, in Kaneohe and Kailua on the eastern windward side, and at Turtle bay on the North Shore.
So, hopefully with the popularity of Disney fireworks worldwide, Aulani will do something special as well. I know that a fireworks show was presented for our grand opening and on New Years. So, it may be safe to say that Aulani will do a fireworks show on the 4th of July, but if not, there will not be a shortage of options for you to experience them on the island.
I hope this helps out a little. Please let us know if you have any more questions, Mahalo!
With Warmest Aloha,
Je'Kay
Walt Disney Travel Co.