List all the mistakes you made, from screening to accepting late rents. 

I am 23 and married and just about to finish my bachelors degree this Summer.

I especially agree with @Jay Hinrichs that being brought in mid-stream without disclosure upfront is not an acceptable practice. 

@Seth Quade how long does someone need to prove they've turned their life around before you would accept them?

Explain why you need them to vacate the property and the benefits of accepting cash for keys, such as avoiding the eviction process and potentially receiving a financial incentive to help with moving expenses.

Appears the PMC has done a terrible job of communicating expectations with you about their services.Regarding the tenant that wants to pay 12 months of rent upfront:1) They better have great credit or no-go.2) Have them prove they are an engineer with a copy of their degree.3) Get last year's W-2 to prove they were working. --- How will you know W-2 is not fake?

We're a couple big manly men so we go upstairs and there's a couple bedrooms and a small bathroom, but it is crazy cold up here, like ten degrees colder than it is outside at least.

(If no it is premature for them to even be looking for properties unless it is very close to the last day of the month so they can give a 30 day notice quickly.)2) Has SEC 8 already reissued you your new landlord packet (RFTA) that you need to submit when you get accepted for your next home?

When I allowed HH properties at my company, we screened people to the degree we could (credit, background, income, rental history), but you still end up with some percentage of "crazies" who can derail the entire property and force out your other tenants.  

You could give them a final notice, a written warning that you are done accepting late payments.