@Chris Williams Well, you can find data online showing RE trends, incomes, employment, etc.

What do you do to ensure that the tenant is responsible for security deposit disputes since that is the largest reason for owner lawsuitsHow familiar are you with the newly changed laws that can affect you the owner if they are not used correctly?. 

I will definitely ensure whatever price I purchase the property at I still have room to cash flow on renting it out.

Financing the debt at below market rates would ensure that it'll make business sense for you not to refinance that debt for quite some time, keeping his payments secure. 

What do you do to ensure that the tenant is responsible for security deposit disputes since that is the largest reason for owner lawsuitsHow familiar are you with the newly changed laws that can affect you the owner if they are not used correctly?. 

How do ensure they have the property under contract beyond taking their word for it?

It's supposed to ensure there are no surprises after closing.

One, is that I can only measure the effectiveness of different marketing strategies if I have good consistent data..Cold calling for example.

My advice if you're going to buy a multi-family from the MLS using your VA loan, as @Joe Funari suggested, shoot for a trip-plex or a quad, and negotiate hard on the price to ensure that you don't over pay for the property (even if you are buying it off the MLS).  

@Tariq K Frantz thank you for sharing the data and your insights as well.