Payments are to be handled by outside/3rd party escrow (mortgage, taxes, insurance, etc), vendor to be determined prior to close of this escrow.  

Or should I just send them a letter of non renewal of the lease?

This means there can be no non-owner employees working more than 1,000 hours per year. 

I have seen one bad tenant crush an entire 4 unit building with bed bugs, non payment of rent, and drive good paying tenants out of the building.The location is the # 1 priority, after that asset condition is really important.  

The only difference is the seller is behind on payments, which is irrelevant if the sale covers all the debt and can occur before the foreclosure sale date. 

Save some money on the down payment so you can put more down on other investment properties.I will tell you the same thing I tell all of my customers, If you cannot find a 2-4 unit or investment properties that will cash flow out of the gate - Look at other states.

In this scenario, you are lending money to yourself as an individual, it allows you to make regular mortgage payments to yourself rather than paying the P+I to a bank or other lender.The first step is to qualify for a Non-Arm’s Length Mortgage with a financial institution. 

You can also bring on another investor to bring the money for the down payment and fund the remainder with debt.

Second, and probably less messy, issue a notice of non-renewal as he obviously doesn’t care about the rules.

Your profile mentions that you are a real estate agent - You want to have a conversation to see if you potentially are eligible to claim real estate professional status which would allow you to treat your rental losses as active instead of passive.Also have a conversation if you are required to make estimated tax payments since there is no withholding on your commissions.Lastly, your profile mentions you are in Florida which does not have a state income tax which opens you up to more options for choosing an accountant.