Traveling to Maui, Kauai, and Oahu in July - What should we prioritize on each island?

My fiancée and I will be honeymooning in Hawaii the end of July/early August and are looking to hit the best of each island. We’ll be spending seven days each on Maui and Kauai and four days on Oahu.

My initial research (though limited) has me thinking of doing more activities on Maui (snorkeling, boat tours, etc.), exploring/relaxing on Kauai (hiking, hanging on beaches, relaxing), and then Pearl Harbor, golfing, and exploring around Waikiki on Oahu.

We plan on renting a car for at least a few days on each island so traveling shouldn’t be an issue.

Am I way off base trying to break it down like that? What are some can’t miss things on each island? Any suggestions/changes to the plan are welcome!