You and your wife are a great example of what you can achieve if you use all of the resources at your fingertips!

While there is room to force equity and recapture much or even most of your cash investment through refi, it is pretty tough to get is all back and truly achieve the so called BRRRR...at least that's been my experience. 

The reason I ask is that selling the home and using a 1031 exchange as suggested above would allow you to either buy a couple of properites in all cash (depending on the total amount of liquid capital), OR you can diversify across several properties at 20% down to achieve $300-500/month in cash flow per property.

Congrats on achieving that status, that's really something to be proud of.

How can I achieve the lowest money down to buy that house?

Again, I know there are great multi-family deals out there and tons of success stories, so I'm not saying they can't be found or that they aren't successful.However, if you could achieve the same results with one or more higher-quality single-family homes that cost just the same with less risk, are in nicer areas, and attract a better quality tenant that pays on time, doesn't trash the house, and is pleasant to work with - which would you choose?

Keep putting one foot in front of the other every day and you'll achieve your goal of early retirement!

The one question that came to mind is this:  is the home really currently in shape to achieve the $1,700 of rental income with $0 in repairs, capital expenditures, etc? 

Using 70k cash, pre-approved, and 800 Credit score, I hope to achieve the goal of getting $150-200 per door after house hacking one year after living in the property. or i can invest in a single-family unit under 250k with 20% down and hiring a PM, not sure how much i can profit after taking into effect all the expenses. 

Reason why is, deals come up all of the time and if you just start buying deals haphazardly, they may not be helping you achieve goals.