The Paul Gauguin is a wonderful ship with an amazing crew of friendly wait staff. We've cruised with them twice and we highly recommend their line. Snorkeling is amazing in most of the ports. We especially loved the pure snorkeling tour in Bora Bora. There are others who cruise on the PG every year who can answer your question about itineraries. The PG only cruises in this area all year long so they have the most experience and best connections for excursions.
We stayed at the Hilton in Papeete for a few days before our 8/27/22 sailing. It is a gorgeous hotel and much closer to the airport and the ship than where PG puts a lot of their guests (InterContinental Tahiti) which is crowded and old. Just my two cents.
Book it! You will love it!