However, there are many good resources to draw from to educate yourself.Having invested from out of state for over 16 years I am well familiar with the process.

For primary residence cash out qualifiers will look into your DTI, you can cash out refi as much as you want.So to answer your questions if you pay back the HELOC you are out of cash and need to draw again if you have the cash out money its has already injured some costs so it's better IMO to deploy it to new investment.  

You need to calculate your net cash flow taking mortgage, property tax, maintenance, vacancy, insurances, property management, utilities and whatever other cost you have into consideration, it should cash flow after paying all these costs( and personally I also stress test whole thing with lower rent and higher interest rates just to be sure).

What percentage should be taking in consideration when calculating the MAO.

@Kathleen McCabeWhat you are not taking into consideration is other expenses like capex and maintenance.

@Evan HaagThanks for the advice, I’ll definitely take every piece of advice into consideration.

@Ry Eikleberry, The most critical component of success in any venture (and real estate is no exception) is your ability to draw a team around you. 

I literally spent 30 minutes drawing up the offer, sending it to him for signature, and then mailed it to the listing agent that night.

@Greg Pasquale this will probably be mentioned a lot, but have you given any consideration to house hacking?

While trends are great and we like to incorporate them into homes we rehab, I think it's important to take into consideration the style of the home.