I have family in Nashville and am looking to purchase/relocate a primary residence in either Franklin, Mt. Juliet, or Hendersonville area in the $250-500K range.  I would also be interested in partnering with someone ...

While meeting a pest control expert there, the tenants adult daughter said they threw away their mattresses about a month ago.

The value today is irrelevant when determining depreciation basis.Cost segregation studies are not cost advantageous for a single family residential rental so no need to go there.I suggest that your grandparents might be better off selling the property and using their tax free §121 capital gains exclusion. 

About 50+ investors show up to buy and sell exclusive (non-MLS) wholesale properties.

A separate Rental Application MUST be completed and signed by each Applicant and all adult Occupants 18 Years or older (Unless a full time student living with parents). 2.

He has one or two adult dogs, that need to be caged in, that's problem one.

And never sign an exclusivity agreement with a broker....bad idea.

What process does a parent have to go through to have a adult child leave if the person refuses to leave?

1/2 tax free from the primary residence exclusion and the remainder you can 1031 tax deferred into another investment property. 

Now that they pay it, it's down to $75/month.However, our 6-plex (10 adults 3 kids) runs about $81/month for water/sewer, but our water rates are obviously much lower.