I'm a retired engineer and have been successfully using income from these houses to support my retirement without dipping into retirement savings.I'm transitioning my business from rentals to a franchise and would consider selling one of my houses (5 br/4 ba - the other houses my son while he's still attending).

This arrange that you will have will likely be a headache(major assumption on my part).First - Do not do business with a friend. 

A business address?

I like doing business there.

Quote from @Blake McWilliams: Using and running a CRM is what you need to help the business you have in real estate grow.

On top of that, hiring tribal members for construction or operations could qualify for employment-related tax credits.

Agents on teams will get leads, learn the business and leverage the team for their higher income and future business success. 

To support my seller and seize a valuable opportunity, my business partner and I decided to purchase the property ourselves.

I have not looked into this but, if process ramps up, could cut construction costs, time to market and massively increase supply, too. 

I’ve heard of a few different options but would love to hear your experiences, especially if you've used gap funding on flips, new construction, or commercial projects.