Hi Crystal, to answer your questions:

Embarkation time - we've sailed the PG twice and both times boarded before 3:00. The first time we got there about 2:45 and boarded, no problem. Last time we arrived at 2:15 and were held in the Grand Salon (with champagne of course) until about 2:30. I think that the last passengers disembark about 2:00 so I probably wouldn't try much earlier than that.

Storing luggage - not sure about that. I'd ask onboard. When you get off the ship, your bags will be under a tent (no terminal building in Papeete). It's possible the ship's staff might let you keep them there as other passengers are embarking. No guarantees on security, though. There's also a Tourist Information office at the pier that might have suggestions.

Scuba - don't know about lessons - we had our certifications when we went. The dive staff is very good and takes good care of the divers. They offer certification courses on board but I think that would take away a lot of the time you could be enjoying Tahiti, as you would have pool drills and book work to get done. I am not sure what they offer in terms of "resort dives" where they would take you on a dive without certification. Dominique (or whoever the dive master is on this sailing) will be at his desk in the reception area the first afternoon - I'd ask him. The staff was very accommodating in fitting in everyone who wanted to dive as well as helping arrange "specialty dives" with local operators for those interested in that.

Kayaks - we are not positive about one-person kayaks but they do have two-person kayaks that we have seen used by one person. You can kayak off the water sports platform and they will have the kayaks at Motu Mahana and the Bora Bora motu.

I wish I were going with you! :)

Dena