To simplify the scenario I'm envisioning let me put it this way: what does a BRRRR look like when one of the parties contributing to the down payment and rehab costs ultimately ends up being the renter as well?

Several years ago when the low flow toilets came out, some just didn't work well at all.

Any recommendation for the first steps I should take if I want to purchase my first rental property using the BRRRR method (or flipping).

It’s actually working really well and has been very helpful.

3.Rent schedule available, as well as lease and income reported to the IRS4.Not sure by what you mean doing it through the city, are referring to rehab permits?  

Well, of course it depends on the individual circumstances, the amount of time comitted and the capital available.

The type of the neighborhoods where his properties were located didn't fit in with my plan but he did well and the purchase costs were low.

Eventbright is a great resource as well.

QB really is not made well for landlords and landlords leave QB every day for better software, payment processing is really expensive, and with QB there's no tenant portal for your tenants to schedule payments or push maintenance requests. 

We've come to know him and his family quite well over the years and I can't say enough good things.