A couple of year ago I paid off my rental with the cash out from my home refi (lower interest and saving $ for paying it early).

If you're looking for STRs on the beach, you'll have difficulty finding something that cash flows unless you can get optimal occupancy. 

The land is twenty acre parcel, which if we buy it, plan to hold it long term to develop either residential or commercial with partnership or cash out for retirement.

HOWEVER, I do personally make over $100k/yr cash flow from 16 properties here.

What are you doing with the money you earn from your job?

Better yet cash out refi? 

My main concern is the limited cash I have available for the down payment and renovation costs.

My strategy would also be going for more price appreciation than cash flow. 

Always have a cash reserve on hand, maybe twice what you think you'll need.  

Finally, other tax deferral strategies prevent you from getting immediate cash, and your stated goal was to get cash for a down payment.Either this firm does not understand what you're hoping to accomplish or they are not being straightforward with their promises to you.