I'm trying to figure out how to use OPM to repeat this procedure, as it's been very lucrative for cashflow. 

I believe the loan does not affect your DTI either. 

Instead of leaving the house vacant, we are purchasing in a fantastic STR market, so we will prepare it for rentals and list it through Airbnb, etc.Now, I am not sure how this STR income will affect us when we sell the house (completing the live-in flip). 

Then repeat.

Also, not sure how this affects anything but there was no listing agreement with the agent.

It was the same price as all the other 2 Family Properties in that particular block.But my Internal Rate of Return Analysis (IRR) told me that given all the factors that affect the future cashflows of this property in this area, that this was going to be a great deal.in 2013, I sold the property for $675k in order to buy a Bed-Stuy property.The return was astronomical.

What alarms me is so many folks dont understand what contingencies are and how they affect a buyers/sellers ability to close - a finance contingency is a courtesy from the seller- which also means the buyer can back out if they cant get funding.

How does that affect who is responsible for the remainder of the original loan balance? 

I have repeatedly asked for the covenant since September and each time they said their lawyers are working on it.

Rinse and repeat!