2 pennies: You could consider expending your search to Bartlett, Lakeland, and/or Arlington.1.

How long are you planning to live in the home and is the 40K expendable?

I don't have that kind of expendable money.

At this time, we don't have any rentals in Nashville and the other two mentions only self-manage.We are open to expending to the Nashville market but if you would prefer someone who is already there, I can get you a couple names. 

There a quite a few post-war (1946 - 1955) houses around here with 9/12 or 12/12 pitched roofs which are still sporting the original steel.You can paint them, but unless you expend the effort to prep the metal, the paint may not stay all that long.If the roof is near the end of life, consider replacing it with a new steel or aluminium roof .. they will last 2-3 times longer than asphalt shingles.

By expending most, if not all of his cash, it would make more difficult for him to do a deal in the future without selling his first property, which he may or may not want to or be in a position to do.  

You are expending more than that.

SIGH;  There's so much a capable DIY'er can do that it's easy to cross the boundary for CODES and/or ZONING.Hope this saga helps others to note that major structural change and/or adding a fully self-supporting area for the intent of renting needs to verify local ordinances before expending time/effort/money.

High dollars for effort expended.  

You would be better off actually learning how Section 8 works in your area so that you don't end up paying extra for some feature that won't net you any more money, and might even cost you money in both capital expended for the feature and reduced net rent ...