If you are not planning on doing the management, and in today's world it doesn't pay very well for the time,  then you can look for the best market posable. 

It may sound nice to pay a 6% management fee but the extra fees can add up to be more than the other company that charges 10% with no additional fees.

So I did not pay extra for it, but chose it anyway over other places.

@Aaron Bard- plenty of  lenders  offer  DCSR loans ...contact a  few  for  quotes ...also - dont  pay  any  lenders  at the beginning of the process 

My plan is to buy the house subject to their existing mortgage, renovate the property, refinance it and pay off their remaining loan balance using the money from the cash out refinance.

It looks good) I stumbled across someone locally who does it, but I'm sure you could find someone there if you or other out-of-town investors like the idea of paying a bit more for that level of security and obtain a remote monitoring source of the exterior of the properties.

both have 5yr pre pay penalty. 

Most landlords wait until the tenant stops paying rent before learning how to deal with it, and they are always behind the curve.

I will be managing and will be paying a real estate agent friend to show the properties for me.

You have to disclose all of this when you sell, so you will end up paying your plumber or discounting to your buyer.