It looks like you are calculating based on cash on cash, but I'd think you'd want to include some financing/debt service etc stuff in there too.There's nothing wrong with buying something for cheap. 

I like different real estate listing services for different reasons, Redfin, Realtor, Zillow, Trulia etc. however they all seem to give vastly different property tax estimates that can take a property worth considering offering on to one that simply wouldn't work.

If so, do you have any reviews for this service? 

For instance, what if the tenants see a big issue that you cannot immediately service and elect to pay rent over to the court causing you to experience financial strain or even default on your debt obligation?

Establish a propsal , seek investor and actual have something to offer them instead of realtor services. 

Since the taxes are unpaid, it is likely the property is paid off, unless he has a lender/loan servicer that is just being lazy and allowing unpaid taxes and fees to accrue.

First thing's first; I'm not in the military but THANK YOU FOR YOUR SERVICE!

They are more focused on having you sign up people under you to achieve overrides (commission) on loans they may close.

You don't want another service call on this stove in the future.  

I work closely with US military everyday to keep morale high and to keep service members connected to home and family.