Suggestions for omiyage for your relatives and friends:
1. coffee
2. calendar with Hawaii photos
3. whiskey (either buy here or at airport duty free)
4. HUOA pin (buy at festival)
5. Some kind of macadamia nut candy (chocolate-covered, etc)
6. Local kind cookies
7. Hawaii t-shirts
8. samll packets of beef jerky (Costco)

Tipping in Okinawa is not required, but as a gesture of thanks I leave a small goodie bag for the housekeepers everyday. I leave candy with a note in Japanese "domo arigatoo."

You may meet someone that you may want to leave an omiyage. Have some small packets of candy or better yet, the HUOA pin. The pin is small and easy to pack.

The hotels normally do not supply alot of hangers (maybe 2 or 3). Bring extra throw away wire hangers.

Okinawa accepts the same kind of electrical plug.

I'll check with Naka's if the hotel has hair dryers in the rooms.

Bring a wash cloth or disposable wipes or waterless soap to wash your hands after using the restroom. Many of the restrooms do not have soap and towels.