#1 is to really really figure out the mindset and behaviors that got you there in the first place, and make sure they don't come up again.

The two ways to change a property's value is to alter market behavior or to alter the subject's qualities.

Sounds like it's time to stop this behavior.

It's almost guaranteed they will pee, poop, and puke everywhere and there's a very high risk of chewing, scratching, barking, digging, or other bad behavior. if you're going to do it, the cost needs to be significantly higher, like $500 or more.

If you can’t parent your children well during a showing (when you are probably on your very best behavior)....I can’t imagine what it looks like when no one is watching.

Look for violations outlined in your lease and keep hammering those....at best you can find enough to warrant eviction, but by the time you do that, it will be close to the lease being up and then don't renew.You won't change this behavior...at best you lessen the issue until you kick them to the curb......

While I don't think she did anything illegal, there is no question that she has engaged in a lot of very unethical behavior.

You obviously want to build a solid, long term relationship and reward good behavior. 

Hey - I'll bite and display my lack of knowledge - just what is a KP? 

Sorry but that’s BS behavior on the sellers part.