In 2019, we VRBO'd in Kihei for a week and then stayed at the Sheraton in Kaanapali for a week. I preferred Kihei. It was closer to the things we wanted to do and had plenty of food options (not that Kaanapali is void of restaurants, though). I think VRBO are more common in Kihei (someone please correct me if I'm wrong on that), as Kaanapali felt more like big hotels (Kihei has those too). Having a VRBO was nice for cooking breakfast and packing lunches for the beach. We'd eat out at night and then walk beaches around sunset.
The Sheraton in Kaanapali was a bit run down but it was on the beach at Black Rock, which is good to snorkel, but crowded. Saw a reef shark there which was cool. But wouldn't stay at that hotel again if I went back. We walked into the Hyatt for a luau and it was much nicer.
You're really not going to go wrong with your decision. Snorkeling was great up and down both coasts. You can take a boat out to Molokini and snorkel there, too.
If you do Haleakala sunrise, spend your first night at the airport hotel and then drive to the mountain from there. You'll be early anyways and it shaves a ton of time off your route. Take a coat.
Also, the road to Hana not be super fun for kids. You have to make it an adventure. My son liked the Garden of Eden. I'd suggest staying one night in Hana, otherwise it's a really long, exhausting day and your wife will hate you and bring it up years later in random arguments. Go to the black sand beach the first thing in the morning after your night in Hana and you'll likely have it to yourselves, as the day trippers don't arrive til later. And ride the horses in Hana. It's a great view the whole ride.
Our last trip was like this:
Day 1: arrive, airport hotel
Day 2: Haleakala sunrise, road to Hana. Stayed at the nice hotel there.
Day 3: black sand beach, horses, finish road to Hana and stay in Kihei.
And then rest of trip split between the two places discussed above.
