He plans to cash out his pension plan and use it as downpayment to the house.

Any and all constructive ideas welcome other than telling us we shouldn't have purchased without a surefire plan - we know :)

The seller needs moving money, there are oftentimes an arrears that has to be paid on the loan, there are oftentimes HOA fees that are due, there are title costs, there are escrow costs, usually there is deferred maintenance, you have to make mortgage payments out of pocket until you get a renter in there, you have to pay utilities and taxes, and you need reserves in case it all doesn't go as planned.3.

I think this calls for another patented day of Mike's Research Plan.

If you have a job you're not planning to quit anytime soon and you don't need a quick paycheck to suport your lifetime I think BRRR is definitely the way to go. 

Over time, I plan to refinance to help create even more cash flow, and with time, rents will most likely increase.

If you prorate do ask them when they plan to stay until and are they staying until the end of the month or do they want to give you a date now that they will leave because my guess is they aren't leaving on day 20.

Your cash value grows tax-free (with proper planning), providing you with an ever-increasing resource to fund your real estate ventures!

I have a plan to buy my entire block in the country.

IMO it would be worth paying a local attorney who performs evictions in the area the property is located for an hour of time to put a plan together to make sure you don't accidently do anything out of bounds.