Haven’t been on PG since Ponant but you used to be to pre reserve dives by calling them; I think it was 60 days out. It would be subject to clearing medical and experience requirements when on ship. Itineraries with the Tuamotus are very popular with divers.
This is correct as far as marina platform for non diving activities. Only SUP and kayaks now. Used to do waterskiing but boats could not go fast enough in the protected lagoons. Also windsurfers but no longer; several instances of having to fetch some who went far away from the ship. Recommend doing either paddle board or kayak on Borabora motu; heaven on earth