It seems all kinds of people don't like Airbnb and don't like renters.

Check your lease, but in any standard lease, there will be some clause that says they have to abide by laws and/or not bother their neighbors or cause disturbances, etc.This means, you can say they have violated their lease - which then gives you the right to give them a remedy or quit notice.I have to agree with the others - even if they are sweet, and the notice of violations only boil down to the dogs running around and not necessarily doing any kind of harm - they are now your liability.  

We all know what goes on in bathrooms and what kind of extra care they need.

I suppose my question on this is: Is her simple statement (which came in a text, btw) to me of "I'm moving out," enough for me to take this kind of action?

Not saying it's bad, it's just the way these kinds of things work.

An investor can enhance returns in the SM all kinds of ways. 

Sorry i have no pity for that kind of self-inflicted stupidity.

The tenants in the 3 bedroom rental aren't in a protected class but I do not want to get in any kind of legal bind. 

It's... not an ideal situation and we're kind of working our way through the grieving process.

What kind of help do you need?