I actually do feel really bad he was so negligent for his buyers over a few hundred dollars in negotiations.

It's normal for a listing broker/agent to leave the buyers inside alone with THEIR broker/agent if they want to talk freely about how they feel seeing the property.This is when having the listing broker there or the seller can be a negative.Having said that a listing broker SHOULD NOT let the buyers out of their site when inside of your property alone when they do not have a buyers broker/agent present.They also should NOT use any part of your property as an ashtray outside or in.It sounds like to me you hired the wrong person.I would be calling the head broker of the company and asked to be re-assigned a new listing agent and tell them what happened.If the principal broker cares about their company they will take the incident very seriously.If they are the head broker then ask to be released from your agreement on grounds of negligence.

Ensure that your lease provides for termination for violations of law or ordinance and for your indemnification for any loss arising from thier occupancy/lease regardless of any contributory negligence or legal liability.Parrrrrrdeee, Parrrrrdeee !

Insurance covers your negligence, that's mainly what it covers. 2.

There are certain situation where officers/owners of the corporation can be held accountable for the obligations of the corporation, but these are typically cases of negligence or "questionable" conduct.  

Not sure how they do things in Tennessee but in most states you're on the hook for the security deposit regardless of any negligence on the part of the PM company.The PM is your agent working on your behalf.

There was nothing unexpected along the way that should have caused time delays, it's just his negligence. 

The effect on their commissions is pretty negligible after the brokerage, business and government take their cut.

I do not agree. the repairs were not made due to negligence of the tenant so no other payment other than rent is warranted. the amount of the water bill was deducted and  as always payment will be on time."

Sure, using a turnkey is not as profitable as doing everything on your own, but if you are a longterm buy-and-hold investor I think the profitability difference becomes negligible over time.