My interest are house flipping and the BRRRR method.

The cost associated with insurance for not having 20% is peanuts compared to what you potentially can do leveraging your down payment. 

There are mortgage recast calculators online or you can reach out to your lender.P+I payment will go from 2155 to ~1800 given the numbers you provided.

Successful realtors prospect for listings using the same methods as investors.

If you are going to be an owner-occupant, want a low down payment, and are planning to do a renovation, the FHA 203k and Fannie May Homestyle loans are your best optionsHow do you know the property is currently upside down on the mortgage? 

It allows you to take advantage of a low down payment loan.

If you’re using a car for business, log your mileage or depreciate the car; whichever method is favorable to you.

Just curious - what sort of down payment do you usually require of US citizens? 

If you’re patient and methodical, though, cash flow can absolutely become a reliable income stream.Hope that helps!

The rules and payment standards vary significantly from one area to another, so familiarizing yourself with the local housing authority's procedures is key.