Thanks for the interest in the garden club now called Verde. We are setting up a yahoo group that you will be able to join and learn as we do. I will post more details later.
On your questions
1) I still am learning about the plants that will grow on the cayes. I too an interested in a green fence for security. It's sounds like a tough spot to grow in. I will have to get back to you on this.
2) Importing seeds. Yes you can bring in seeds for personal use without duty. They have to be in a sealed commercial package, seeds packages from the store. They can not be GMO (geneticly modified organism). Restricted items are plants and the soil on them. I am still checking with Customs just to make sure. More later...
I would reccomend getting seeds that are not hybrids, as these will not come back the same variety from seed next year. So you would have to have new seeds every year. Look for varities that are considered "heirloom" or "open polinated". These are the varities that you will be able to save seeds from year to year and always get the same plant or vegitable. Some good sources are Seed Savers exchange http://www.seedsavers.org/
, or commercial seed producers such as Renee's Garden http://www.reneesgarden.com/
( I personally LOVE her seeds).
I hope this helps to start.
Our next meeting will be Thurs. June 12 2pm Island Perk. We will be discussing a quick beatuifaction project we can do and my favorite subject COMPOST!!
Thanks for the interest.