I'm sure the Transat thing was a one-off, once in a life time thing. I hope, anyway! Just be prepared to be cramped, the seating is CRAMPED!! You can go online and reserve what seats you want, if there are a bunch of you going in the same plane. It does cost money I think though. It's on the transat website.
The ceremony was right out in the middle of the beach, so not private at all, but they did help with moving people out of the way when it came time for the ceremony. But there will be people watching for sure. There are a number of really nice areas around the resort to pick if you want it more intimate. Pretty much anywhere if you ask, they will set you up where you wish.
I'm not sure what you mean by the reservations. Things might have changed since I was there last, because we didn't need reservations at all except for the one dinner that came with the honeymoon suite package (which was the steak house or seafood by the ocean). You might have to check with the other girls on that one.
My goodness, less than a month! You must be bustin!!