$300k/1945 is 154 months (12.85 years) to have the cash flow recover the additional down payment.  

The 4% interest rate is an important part of this calculation because the principle paydown portion of your payment is significant, I'm going to guess it's about $9k per year.

Likely due to the recent hurricane Michael.we have included coverage for replacement of lost rents for at least 6 months, to cover us for the mortgage payments if a hurricane destroys the property and we have to rebuild.  

Collect lien waivers (especially if the payments are passing through an intermediary GC).5.

There are a lot of local lenders that charge a 1% origination fee and the interest only payments during construction are prime plus .75 - 1.0%.

That said you could ask for a statement showing their recent payments.

I hired the professional guys for this and it cost about $4500, but that was for the whole friggin basement.The other thing that I would do is to tell this tenant that they are welcome to leave and move out and go somewhere else at any time, and I will gladly let them out of their lease early providing that they are current on their payments and haven't caused any damage.

Are you looking for lowest payment possible and maybe an interest only or variable rate (but that has higher risk).Once you define what it is you need, then you should start speaking with lenders and ask them what types of products they have for what it is you need.If it is a traditional lender and they are licensed through the nmls (google nmls consumer access to find them), then that means they have been vetted.Note that most lenders DO NOT keep their loans and they get sold, so age of company is usually not important, experience of originator would be more priority for me

I provided an up front $10000 earnest money payment and then secured a monthly interest only loan with principal being paid upon final sale.

became our holy grail.We tracked payments with paper notes and consistently followed up with residents about small delinquent balances.