Maypops do not get large enough to cover 6' high and 300' long chain-link fence, do they...? Unless you plant 100s of them..

300 feet of passionfruit could put you into the juice business.
With that much fence to cover, you might try planting some of the tropically adapted annual climbing vegetables which should actually do very well during summer and into fall.
angled luffa (Luffa acutangula)
bottle gourd (Lagenaria siceraria)
ivy gourd (Coccinia grandis)
winged bean (Psophocarpus tetragonolobus)
seminole pumpkin (Cucurbita moschata)
west indian gherkin (Cucumis anguria)
true yams (dioscorea alata)
yard-long beans (Vigna unguiculata subsp. sesquipedalis)
hyacinth beans (Lablab purpureus)
malabar spinach (Basella alba)
jicama (Pachyrhizus erosus)
korilla (Cyclanthera pedata)

For a (semi?)perennial try chayote (Sechium edule)

This site offers seed and very good instructional videos on cultivation of many of these, she is in Florida.
https://www.asiangarden2table.com/grow-asian-vegetables/beans-peas/

As I understand it, biochar also sequesters nutrients, and doesn't provide any as it doesn't break down the way organic matter, but rather acts only as a reservoir.

Haven't been there for forty years, but in those days boats came over from Columbia/Venezuela with fruit and veg to the docks in Orangestad.

videos of Truly Tropicals:
https://www.youtube.com/watch?v=VmCpNnnRqgE

https://www.youtube.com/watch?v=doTF0IE0MWk

When I lived in the Caribbean I had one of these. You had to throw it in the sea for retrieval, then 'Spot' would tear them open! She enjoyed a small part as reward. Not trained, but exactly like this one I found.
You could probably train for it, though.

https://www.youtube.com/watch?v=fhH0XXiN7lo

This discusses passionfruit pollination:
http://nhmj-ioj.org.jm/ioj_wp/wp-content/uploads/Observations-on-the-Pollination-of-Passiflora-penduliflora.pdf

Shows how to hand pollinate:
https://youtu.be/HFx92jfdkzo

https://www.youtube.com/watch?v=eicamZk1qis

Sounds like for best fruit you need bumblebees, hummingbirds, and plenty of different plants for compatibility, and pollination was best late afternoon/early morning.

There is a US ministry group which has been working to send thousands of breadfruit to Haiti in the past. I saw a youtube video. Try searching Haiti breadfruit. They could probably arrange shipment and distribution.

Guava should be easy enough to grow by cuttings, and would be an exact clone.

 http://motherhood.modernmom.com/propagate-guava-8826.html

A single stake might be fine for a 1-2 ft tree without much top growth.
But a 5 ft tall tree with a single stake into the root ball wouldn't do much to keep the entire tree from tipping over especially if the ground gets saturated, the whole thing might just be tipped over. Some version of multiple stakes and strap ties might work better.
If 100 mph+ is expected maybe time to do sacrificial pruning?

I know that bananas are quick re-growers, and I've heard recommendations to go ahead and chop them down before a severe hurricane which would certainly topple them anyways.

Hope it goes well. I love my trips to Pine Island and enjoy riding around to see what I can spot.  Good luck!

I hope to move over by this time next year and will enjoy visiting with anyone here.
Property is surrounded by 100 acres of vegetables in winter, they are protected from frost by giant wind machines and I should also benefit.

I've used mechanical advantage like this video to pull otherwise impossible stumps with a tractor.
Rather than a built-up rig, just used a log section about 4 ft long and ran the chain over the top of the log.
You could use a large tractor tire rim as a roller to run the chain over.
It's an old farmer's method.

https://www.youtube.com/watch?v=pccuAUNwfw8

lots of plants respond to stress by flowering. I've heard of (anecdotally) people driving nails into coconut to induce flowering before. What may be happening is the wire is girdling the branch.
There is some basis for this:
https://www.researchgate.net/file.PostFileLoader.html?id=55d96f0d5f7f71eb398b4596&assetKey=AS%3A273837277548547%401442299302550

http://jxb.oxfordjournals.org/content/early/2016/07/04/jxb.erw272.abstract

How does one get one of these in FL? Sounds like it might do well in the Keys climate, and I like the look of the huge dark green heart leaves.

http://ez2plant.com/item/yard-garden-outdoor-living-fru/-chupa-chupa-quararibea-cordat/lid=33906188