Distance between Tahiti and Moorea is around 15km. Water depth can reach 3,000m. Tahiti & Moorea are part of the Windward Islands (Society Islands). If you find these information really interesting, please continue on Wikipedia. If you really don't care at all and you are getting annoyed and still looking for an answer, you can check on the page "Travel and stay".
15-25 years, after time can get long. If you do not have that long, recommendation would be: Moorea: 3-4 days Tahiti: 1-2 days Tuamotu or Bora-Bora (if you still have some budget): 3-4 days
We may arrange a drop off in the lagoon in front of the ceremony place ! No transport arrangement will be done and we highly recommend to stay short walking distance and not drive at night.
Of course, nothing is free in this world ! however, you won't be able to find Pacific Francs (XPF) anywhere except at Auckland or Papeete airport. Best is to come with EUR, USD or NZD and to change at airport. You can also withdraw money at ATM but not all debit cards may work. Credit cards (Mastercard, Visa, Amex) are largely accepted in most touristic places.
Wrong question: there is no dress code. But lighter is always better.
Not your pets, neither your grandmother !
if you wish to give to the local residents of Moorea, yeah of course ! otherwise, as world travelers the most practical gift for us would be money (or at least what's left after all your expenses of this holiday)