I was outside installing gutter screens and noticed a torn window screen and a slightly open window in the common area.

This should be done before you buy your first property but defiantly before you look for a tenant.You need to be especially diligent in screening as you are going to be dealing with the bottom of the barrel tenant pool when it comes to renting mobile homes.

Trying to become informed before investing unnecessary money when there is a better way. 

We also are really diligent on our tenant screening process, because your not just buying a property, your also inheriting a tenant.

With that said as @Mitch Messer go back to the drawing board with the screening process and draft a new agreement including the boyfriend.  

Explain why you're unhappy and be sure to listen to his frustrations, because getting sued is unnecessary time, money and stress.

Are you referring to candidates that you have already completed the screening process on,- credit, employment history, previous landlord etc.

A good GC has a number of subs in their list, at least 5 each trade, or should know how to screen subs, have proper procedures for subs not just picking someone from craigslist, another form of GC has their own crew and only has special subs for special trades.

These people on section 8 know that, and will not do anything to get their voucher revoked. so as long as you do a good screening you shouldn't have any problem tenants who destroy the place. in some cases section 8 tenants are better then non section 8. 

I already see some of my slightly older friends buying unnecessary luxuries that people my parents age have.