Education via trail & error is easily the #1 worst way to go about anything today UNLESS your an explorer, inventor, revolutionizing and still all of those have a whole lot of training and education backing them. 

We still owe roughly $900K on a 3% mortgage.We’re planning to retire abroad and are weighing two options:1.Sell the home – I already have a buyer lined up, so this would be a straightforward exit.2.Rent it out long-term (furnished) – While I don’t think the rent will fully cover the mortgage, it might come close.

He will have a variety of answers to your questions.

All these things have existed for a very VERY long time.

After undergoing a complete renovation, I sold it in 2018.

Bonus, since you are licensed a lot of folks don't want to sell at a discount.

We had a recent court case which said in black and white: you cannot calculate an average if you do not have at least two numbers to average.

Most cities do not allow "boarding houses" and/or have a "no brothel" law. 

In the future, please have all this lined up before you submit a contract.

I understand the sentiment, but I think it will have more negative effects.The problem is with enforcement.