I retain 15% equity in the property and cash flow about $1,000/month

Also, was the Architect retained for construction phase services?

On the flip side, holding onto equity allows you to maintain the proven income stream from your established STR and retain a valuable asset.

I recommend you retain a tax professional.

If buyers ever become responsible for paying my fees, I will probably charge a retainer to ensure I'm compensated for my time even if they never buy a home.

Once approved, we offer a lease to the tenants, collect first months rent (which we retain) and security deposit (payable to owner)  We also make sure they have utilities transferred and renter insurance in place before obtaining keys for move in. 

Common fees will include a set-up fee, a leasing fee for each turnover or a lease renewal fee, marking up maintenance, retaining late fees, and more.

I am sure aa my statements reflect it as well as having a previous move out date which they paid the day of eviction and were able to retain the property.

HOW SHOULD THIS BE STRUCTURED SO I RETAIN THE RIGHT TO MY PROPERTY DURING 5 YRS IF BUYER DEFAULTS ON A) HIS MORTGAGE B) TI & C) OUR PMT?

You would have to retain so much a month that it would kill every deal.