Make sure your lease has some kind of limit for the number of days that an unauthorized adult is allowed to live in the apartment. 

I ask because I have an application that I will in all likelihood be denying as they have 6 children (2 adult) that applying to live in my 1600sqft 3/2 SFH. 

The feds know better than the 2 adults and attorneys doing the deal?

One told me that it will be her, her husband, their young grandson, and that her adult daughter and her boyfriend plan to move into town and stay with her "while establishing themselves."

Once again, we rent to ADULTS, NOT CHILDREN.  

:)The firepit is an easy fix, remove it and don't allow it back if people can't be adults and use it with common courtesy and respect.

I would advise everyone, especially young adults, with very similar advice as reading, keeping positive company, and perpetual learning are essential to a productive and fulfilling life in my opinion.  

I treat them like adults and give them the opportunity to do the right thing or deal with the consequences.When rent is late, I add a late fee.

I buy my adult oriented artwork from various online sources. 

Your tenants are (allegedly) adults and should act like it.