Hi living4experiences,
We did dive in Moorea and Raiatea. We went with Hemisphere Sub in Raiatea and they were good. Very happy with our dive. In Moorea we booked a private dive because of our timing. It wasn't cheap but we wanted to dive there so we bit the bullet. We used Scubapiti Moorea. Email with them wasn't top notch but they got the job done communicating with us. The diving was EXCELLENT - I really wanted to see Nemo in the French Polynesian and we got to see several in Moorea. It was really nice that it was just my husband, myself, the dive guide and skipper. We did not dive in Papeete because we had to fly home. We did the snorkeling with whales and were lucky to snorkel a couple of times with a mama humpback whale and her baby. It was awesome. Not thrilled with the operator though - very hard to find them when we got off the ship, etc... I don't think the humpback whales are there in April, so we probably don't need a recommendation for this excursion.
I hope this helps. We did all shore diving in Hawaii on our own.
Have fun!
cruzbound