Depending on their level of certification / registration, they have a true fiduciary duty that they are required to disclose to you exactly how they are getting compensated - including if they are getting commissions on any of the products. 

I'm in the position to apply(depending on lender DTI requirement) for conventional financing through the builder at <6% interest rate in this current market.

Is it true that a FHA loan will require us to occupy within 60 days?

They required me to have the house and detached garage treated and the termite damage fixed (1/2 of the sill plates, 1/4 of the studs and 1/8 of the sheathing needed replacement).

If they don't perform to the requirements stated in the lease, it is kept..period.

Highly desirable as a rental with the potential to convert the vacant lot to additional STR units.

Typically lenders require an executed contract on a specific property, but several I work with closely issue loan commitments (fully underwritten conditional loan approval) in as little as 24 hours post receipt of a contract and required documentation.

If you can swing it and are willing to do what it takes to not lose the property if sh** hits the fan, then I would highly suggest purchasing in a more desirable area. 

I am in Florida, which requires written notice for rent increase.

All buildings close to the beach requires piling on the first floor then you can either add 2nd or 3rd floor depending on your business plan.You can reachout to real estate agents that are predominant in the area to provide you with short rentals income report.Let me know if you need any help or info about building ground up.