Jaron is right, don't fully dive right in without testing the water first.

In my opinion, a CPA knowledgeable about the asset test rules is a better resource than an attorney in terms of ongoing compliance.  

Also, take as many practice tests as you can, as often as you can. 

Study study study on deals, it sounds like you may have a deal but yes the 10 years vacant is a huge red flag (buildings in this area for example have iron pipes that collapse when the units go vacant for extended periods and cost tens of thousands just for that, do a sewer scope test as part of your inspection!!!)

The key point is to stress test your numbers in a range (say .5-1% spread). 

I've tested a few apps & none of them are that great & have completely different results, as I'm searching primarily for multi-family properties.

Test it by paying for 2 appraisals -- one with and one without an active contract. 

But that will cover the sniff test  and then you can decide.As others have mentioned unless things have radically changed in Memhpis a 140k house is a pretty good area and good house and should rent for that 1200 number.. or more  not 950.. that's the first problem with your math.

You can get a little kit from Home Depot and test it.

Once that is complete, you will then be required to get testing done as well as fingerprinting and selecting your Broker to hand your license.