Welcome Linda!
You are going to have such a wonderful time. Moorea is so beautiful, what a great choice for a pre-cruise.
I can only answer one question, sorry. You do not need reservations at L'Etoile. It is the main dining room on the ship and you can be seated any time during dinner, either at a table by yourselves or with others. La Veranda and Le Grill require reservations. I think they are both worth trying at least once. You can make your reservations ahead of time on the RSSC web site. These reservations require you to choose a time.
I hope this helps.
Jill