If you go modular you have to start modular with your design so find an Architect that has done it before.

I think the best approach to this situation is when dealing with (beginner) investors who are referencing properties they have seen on Zillow, show them the margins of those properties compared to properties you are have available.

@John King, I do have magnetic signs on my car and have had different designs for at least 6 or 7 years.

I won't pretend they don't like to spend, but they all know it's important to Save, and more importantly to Invest.I think it important to present a consistent overall approach but that drilling daily/weekly about the importance of specifics might be overkill. 

The house is not on the market and I need to approach my landlord about my interest in purchasing the house.

About 18 months ago, I attempted a similar approach with a SFR in a rapidly gentrifying area. 

Buyers approached me to purchase a house in Mississippi that I can get for $40,000 cash.

And what approach should I take if they are not open to rent-to-own?

I closed no business and learned much less from the experience than I thought I would.Now, a year has passed and I have adopted an entirely new approach to my mentality about this entire industry. 

The smartest approach to investing is to save up the money yourself for a DP.