For most cruises I will take NCL. I like their Freestyle concept and upgraded entertainment. I also enjoy the alternative restaurants and I budget for them.
I have no personal experience with NCL in Hawaii but I do know there were problems but current reports are overall good.
You can pre-order in cabin bar setup from NCL. It isn't as "reasonable" (relative term) as Carnival's but it isn't as expensive as Celebrity's.
For you I would suggest doing the Carnival cruise. I think it would fit your needs and give you a good taste of the islands. Also, it would eliminate the airfare cost. I'm not sure how you would like the number of Sea Days but I love them and Carnival will probably have more "stuff" to do on the sea days than Princess.
When Michelle Roux left Celebrity and the Blau Group took over the dining, Celebrity's food went downhill for awhile. It has come back up but, IMO, not to the level it was ten years ago.
No matter what, I know you'll have a great time. You've received some good advice on what to do on the islands and I agree that a rental car is the best way to go.