I can help with some of these.
We took surfing lessons and thought Hawaiian Fire did a great job. You can walk down Waikiki Beach and do it right there, but there are a lot of people in the area to contend with. When we used Hawaiian Fire they brought us to a more isolated beach and did a nice job of teaching us the basics and then helping us time the waves. I think it would be very difficult to learn on Waikiki Beach with all of the other beach visitors in the area. Also, the staff is off-duty firefighters so I believe they were all certified in life saving techniques.
The key to Pearl Harbor is to get there early and get your time slot for the USS Arizona memorial. For the rest of the exhibits, we did the self guided tours. We also rented players for the submarine tour as it guides you through the sub and explains as you walk.
Diamond Head is a little tricky as it has limited parking. If there are no available spots you are either turned away, or put into a parking queue. We only spent about 10 minutes in the parking queue before a spot opened. A word of warning about Diamond Head, it's not a stroll down Main Street at Disney. There is a significant grade to hike, at the end there is a very tight area to crawl through to get to the observation platform, and I'm somewhat afraid of heights so areas of the observation platform bothered me. I run, and consider myself in good shape, and the walk was not difficult. My wife, though, can walk all day at Disney without issue, but she struggled walking to the top of Diamond Head. Lastly, bring some cash if you want a t-shirt. A vendor had some nice "I hiked Diamond Head" shirts right on the trail, but of course he couldn't take a charge or debit card on the trail, only cash. I was a little concerned about giving $60 cash to some guy on the trail, but as promised, the shirts were all delivered to our hotel by the end of the day and my kids still enjoy wearing them.
For your 17 year old, I would also suggest Manoa Falls. It's amazing to me that you can be in downtown Honolulu and 15 minutes later you are at the entrance to a rain forest that seems extremely isolated. It can be a messy hike if it's rained, but we thought the hike was beautiful, and although the waterfall is not as dramatic as you see in the movies, it's still a nice end to the hike.