If you are raising vegetables you don’t want an in ground garden. Sand doesn’t grow vegetables. You’ll need to do raised garden beds and create rich soil with all the amendments from scratch.

Garden
 

Not sure how you could ever sell the place. Maybe build boxes on top of the concrete as they could be removed by the next owner, which would be pretty much a certainty, IMHO.

Sounds like fun and a great deal of work but I am an avid gardener and am use to that! Good luck. P.S. I think the drainage could be a problem in a birdcage.

Re-emphasizing two key points already made. Don’t do it if you have a pool, best to keep organic matter out of the water. Large pots are the way to go, way less complicated/messy, can easily be moved or removed, and weigh enough so they shouldn’t become projectiles in an intense tropical storm.

It seems like they should be meeting at Aviary.

Many plants depend on insects and pollinators to complete their cycle. Also, the birdcage screening cuts out a lot of sun needed by the plants. I did this with tomatoes and zucchini in college. Raised them ok in a screened area, but pollinated them with a q-tip. It worked, but lots of work. My herbs go outside now. Most strong plants do not have an insect problem.

How about a Koi pond?
 

When we were looking at homes in The Villages we looked at one that have a three level pond with rock overflow into the next pond...all in the birdcage. It was gorgeous! Here is a picture of one I just saw on a Koi Pond facebook page. Also stunning.

We've grown many vegetables in the birdcage using Earthboxes. Any vegetable that requires no pollination (lettuces, greens, etc.) grows well. Also, there are many vegetabbles that are self-pollinating. Tomatoes, cucumbers, peppers, eggplant were all proliific producers. There was no need for pollinators. The wind was enough. As for the concern about less sunlight, it's Florida. That's not a bad thing. We've also grown tomatoes in large pots. They were not as successsful as in the Earthboxes, but they produced. We've also grown 9 different dwarf citrus trees and some figs in very large pots. The trees were fun, but a lot of work for what we got. I actually ran drip irrigation around the outside and fed the small distribution hose into the birdcage. We've been growing food for over 50 years. The Earthbox system, while initially a large investment, provides a substantially better yield than anything else we've ever used.

Pet birds can be a problem for older adults
 

Unless you are in perfect health, I’d think twice about getting a pet bird. They can bring many parasites and chronic lung inflammation from dander and droppings. They are only marginally safer than reptiles or rodents. But worse than fish and small dogs.