But if they don't willingly make the payment your only option would be to sue, and they have the upper hand to let the lender know about the sale possibly triggering DOS.

I see where Sub2 can and has been a good tool in the right hands.  

I'm not completely foreign to the construction process as I grew up around a family that was involved in home building, but due to living in another state I can't really lean on them for the direct, hands-on guidance. 

What I find to be most valuable: Ease of use, cost-savings and efficiency and here's what I mean: If using an interior designer to furnish your rental, they will hand you a list of supplies + furniture to buy and what I was able to do with Minoan is upload that list as a CSV file and then they come back with a quote of all of the items they can fulfill along with their respective discount. 

Always have a clear exit strategy, whether you plan to rent, flip, or sell the property down the line.If you or your son are looking for more hands-on guidance, feel free to reach out directly.

For myself hands down the fastest way to get to Fi is via house hacking. 

From what I read and understand, this means I'm likely going to struggle with getting a loan, not even considering the inability to pay any down payment.On the other hand, my parents have significant liquid assets, (think on the order of > 500k), that they are potentially looking to diversify into real estate.

Depending on how hands on I am.

the essence of BRRRR is to be in-person and hands-on.

I've seen too many investors find a good property, then hand it over to a terrible PM and the entire thing fails.