We were a group of eight, 4 couples. I regret that we did not do the 11 day cruise instead of the 10 day one, one extra port for about $50 per person. Also we flew up the day before the cruise, good thing since our plane had mechanical problems in LA and we did not get to Honolulu until 9:00 pm. I wish that we had flown up 2-3 days before the cruise so that we could have done more in Honolulu.
Regarding Fanning Island we walked around, shopped, (my wife bought a sea shell that weighed about 5 lbs.), bought stamps, watched the native shows, swam on the beach, and ate. NCL serves picnic style, hamburgers, snacks, desert, and drinks. The scenery was beautiful and the swimming was fine, but not much else is going on unless you are into native dances. We did not speak to anyone that did a tour here.
The Wind is not a huge ship. There are many deck chairs, but not so many deck tables, and few are covered. If you want shade outdoors, you will need to look for shadows. However we did not feel excessively hot on our cruise, and actually it was cooler than our climate in New Orleans.
We did the Volcano Nat. Park & Rainbow Falls tour which is 6 hrs. With this tour we got lunch at Volcano House within the park which was real nice. I would recommend this tour to you for just a little more money. We did not do any of the other tours that you listed except for the luau, which was great.
The shows are not the highlite of the cruise. We have sailed on other ships and have seen much better. Also because of the slow service in the dinning rooms, we missed several shows because we were late getting a seat after dinner. The showroom is basically flat, not stadium seating, which makes it hard to see if you are not near the front.
There was one formal night. I think it is the first night at sea heading to Fanning Island. Ofcourse the itenaries for the 10 and 11 day cruises are different so this may change depending on which one you are on. We would have liked two or three formal nights.
I would also recommend doing the LeBistro restuarant at least one of the nights. It costs a little extra, but was a fine dinning experience, and a little slow also. We did it so that the women could get the chocolate fondue, which is NCL's signature desert.
I hope this helps. If you have more questions please write.