With only a $70,000 profit a reverse exchange will eat into your profits quite a bit.  

The taxes really eat into your take home money though, so after accounting for vacancy, common area utilities and repairs, you might make $32,000 a year (.04x800,000) (assuming you’re paying 24000 or 2000 a month equivalent towards renting your 1 unit apartment in your own house) BEFORE paying your mortgage (PI).

And I almost never give unsolicited advice as it's normally against the grain (but since you asked me to comment via DM)I'd take it out, eat the penalty, and use it to buy properties.   

Eat less meat and more veggies (ribeye's doesn't count!)

I wonder how a room rental tenant with a service dog/emotional support animal would be handled?

Because PM fees usually can eat up about 20~50% of net profit.Two of my own personal experiences:About 4~5 years ago, I had an opportunity to choose a similar 4-plex property from two states, one in Texas with property tax rate about 3%, another from a Mountain state with property tax rate less than 0.7%.

Walter on this topic of never paying the mortgage and there is another parallel topic called never eat a vacant month.

Need to watch for lawn maintenance, unauthorized occupants or animals, vehicles parked on the lawn, etc.  

Also realized that small items eat up time and profit, like hardware, caulking, etc.

The Master suite was on one side of the house separated by an open floor plan with the kitchen, living, dinning, eat in breakfast nook, and laundry off the garage.