Another question--would my chance of getting a loan change if I were to buy land first (and perhaps put a tiny home on it later)?

It's not a tiny economy that would fall apart if people suddenly stopped visiting, like most Caribbean islands, Belize or even to some extent Costa Rica. 

I was considering a tiny home and still might build one afterwards but yes I’d definitely be looking at a used mobile home.

I'd say it would be a tough way to make a living in most markets, but don't say anything to the gurus selling the stuff on "how to".If you really want to be in RE, learn RE and get out of the tiny niche market stuff.

I'm looking for a place that requires a little work that is in a nice safe area where I can lease short term and in a pinch also to a long term tenant.I've been looking at Boynton Beach, Delray Beach, Vero Beach, Deerfield Beach... and even taking a very cautious look in the beach areas of miami for a super tiny place (300 sf :) unsure of HOAs although I expect them to be high). 

The property is 4 acres with 5 tiny homes and 1 main house (doublewide). 

Naturally my thought is to add a bathroom and convert the garage to a “tiny home” unit for STR.

If there's still a tiny risk, I don't mind.

Also has the upside of 1 car detached garage that could make a nice little tiny home as well.

The average price for a night stay in a "tiny" home is $170 in my market.