We had 2 very good experiences in Mo‘orea. One was the photographer Joaqin Fregoni who provided night snorkeling, somehow interesting conditions but perfect guide. The other was blue water diving, located in Manva Beach resort who had the best interactions with the whales, which I highly recommend (we tried 3 different providers). Reserve a spot because they usually are fully booked.
For Fakarava we already saw all the reviews and I think we know what to expect.