Also, the terms of the deal are more specific (contract specifically addresses occupancy status, leases, possessions, liens, violations, designates responsibilities and other contingencies). 

What you expect Seller to do before settlement, 5 Possession terms, 6.

As there is no equity, they are very likely to do that.You may need to explore further options if he filed Chapter 13.Either way make sure you pursue your options to collect as much as you can from the court, although with a Chapter 7, that's likely to be near zero.With possession, you can start collecting rent.

She has lovingly filled it with cherished possessions....we truly felt we were staying at the home of a long time friend."

If you already possess significant investment capital, you may be able to learn how to deploy that capital for a greater risk/return reward.If you have limited knowledge of the real estate residential and multi family investment market, you should be able to acquire significant knowledge.Nobody spending $100K on a top tier MBA program expects to learn how to retire in 5, 10, or 15 years.  

I do not have a copy of the appraisal in my possession yet but can anyone shed some light on this?

A primary residence is partially a possession and partially an investment.  

So they have possession of 15% from the sale of their place, are approved for the loan and seem excited to move in but I'm reluctant to allow their items to be placed inside before closing.

I am looking for an investor-oriented real estate agent, in Houston area, who are willing to do extra work (fast and reliable to check properties for me, have the patience to go through several offers, practice an aggressive approach to help me locate good investment deals, possess great negotiation skills to get houses at the right price) for residential properties. 

Not sure about the laws in Tennessee, but in Florida, if they don't move out on their own free will, you'll have to hire an attorney who files a motion with the county court to obtain a "writ of possession", which you then take down to the local sheriff's office to get the eviction.