Because residents will own the homes, you will be moving homes, renovating homes, selling homes, carrying paper, so there are specific contractors you will need to find, and licensing and regulatory requirements that you will need to know.  

And, I fear that if I make her carry out her lease, things could get ugly between her and her roommates. 

He carried the note for 1 year at 6% interest only.

THEN After so many days, make the builder pay your carrying cost (since he is the one holding things up, at that point, you did your duty on the front end.)

After all carrying, costs, remodel costs, finance costs and selling costs we made a profit of approx $40k Lessons learned?

I never carry a balance more than $100 from the previous month.Savings: I have $120,000 in cash savings for reserves and for future projects. 

This is a good article I found on Carry Back and Carry Forward losses https://loopholelewy.com/looph...

If owner will carry the agreement, will the Brrrr method still work?

Properties have all sorts of issues when they're acquired and title issues can be among the most serious as they can prevent you from carrying out your plans. 

I do carry a multi-million dollar umbrella policy plus landlord insurance.