I lend money and would not want to lend on this type of deal.Here are some resources to explore:Contact your local tax authority ASAP!

Ask if their handyman is in-house--which I've seen turn into a "charge up to the owner authorization threshold for every single visit". 

Landlords should not be listed as an "Additional Insured" as that implies they have insurable interest (they don't) and have authority to file claims or receive coverage (such as in a lawsuit) from the renters insurance.  

I don’t know how 2 people got 3 homestead exemptions but that seems like something the local taxing authority could catch pretty easy.

I would let the tenant know that he is not authorized to live there.

I'm a newbie tooSelf education through books is a conversation between the author (mentor) and you.You'll gain knowledge, connections etc but it takes timeAttending meetups, listening to Youtube videos on subject matter further broadens knowledge base

If the airport authority would deed the buildings to me, it would cause them to be entered on the tax roll.

To just make money is not enough.Michael Gerber, author of the E-Myth  said it best in an interview.  

In our area, the housing authority does annual inspections to (mostly making sure the landlord is keeping up the units) review the tenant and the landlord. 

Battery Park City Exchange (New York City): The city of New York engaged in a land swap with the Battery Park City Authority, allowing for the creation of a new public school and affordable housing units in exchange for a parcel of land that was then developed into a high-value commercial property. 5.