Now, I have to repair damages, clean up the property, then find another tenant.

There may be an initially higher cost to get the current infestation under control, but then going forward, it should be just the regular monthly charge.What I'd do, is give the tenant written notice about how you are taking care of the infestation - that you've hired such and such company, details about how they are dealing with the infestation, and how they will be treating monthly going forward, and enclosed is the information the company provided about how the tenant needs to clean up food laying around, and take the garbage out regularly, etc.  

Other small things while turning over a unit is; new toilet seats, new lighting in bathroom, new handles on all doors, new fixtures on sinks, ceiling fans in all bedrooms, supply a washer & dryer in my duplexes, and clean up the entrance area for a good first impression. 

It makes you negligent if something were to happen because you didn't take care of what you were responsible for, and if you were very aware, specifically, of what you should have taken care of, you could be found grossly negligent, if something really bad happened.So, I'd just clean up the mess, tell your tenant you're taking care of everything, and tell your neighbor you'll pay a reasonable cost to repair any damage. 

I am going to start a foreclosures clean up company to add to the list of services I can provide.

The exterior shows its age and may need a little work other than cleanup and a little landscaping.

Making clean up as easy as possible is good for the sanity.

She also does some light plumbing, painting and all cleanup including caulking!

If they don't clean up their poop, you can give warnings and eventually kick them out if they don't clean up, etc.It's really not all that horrible. 

They must keep them leased when outside (if no fence), clean up droppings, immediate notify us of any damages and make restitution on repairs immediately (this is deducted prior to rent), and the tenant agrees to cover any pest mitigation caused as a result of the pets presence.