This may be a stopgap measure but I have news - laws vary from one jurisdiction to another but in general tenants are straw men, they have little to no assets, while injury lawyers see landlords as owners of property that is worth going after in court.

The good news is you still have the keys and tenants are men of straw.

I do not own property in the US but I have rented to numerous Canadian service men and women in the past and presently have two renting.

According to my friend you must make sure to have a parent/gardian/guarantor to ensure the rents are collected and make sure you have a solid structure with VERY durable finished if you plan to rent to men.

They talk the repair men to death too.

If they refuse to pay the bill to restore their handiwork to its original state, deduct it from their deposit and begin eviction proceedings.I understand why young men might try something like that (hey, I was a young man once before,) but they have absolutely no excuse for doing it again after they were caught and warned. 

Schedule your eviction the day before trash day , put it at the curb , when the trash men come , smile , grease his palm and watch the stuff magically vanish . 

The way I look at it, when a tenant (including myself) signs a lease that says you are responsible for cleaning up after your pet, and you can get fined if you don't - they should know that they have to agree to the landlord figuring out how to catch the offenders.And, no, unfortunately, there will always be people who won't pick up after their dogs, even if they agreed to the DNA test before signing the lease.What I've noticed, is it's the men who are the worst offenders. 

Several of my tenants have a stay at home mom that can let in repair men as needed.  

While doing an open house two large men tried to rob me, luckily people started coming into the home for the open house and the "creeps" ran away.Had an applicant's mother co-sign for a house for her daughter.