I would be very careful about what neighborhoods you invest in, though; Cleveland has some serious war zones. 

I care most about the Internal Rate of Return (helps me determine how long to hold a property), the cash on cash return (helps me decide why this investment vs other options, and it also takes into consideration appreciation of the property!)

They've ruined many financial lives and simply don't care. 

I like using these for just this case.Another item to consider is since this is a 2nd floor I wouldn't be that worried since the 1st floor will heat the 2nd floor enough to not allow frozen pipes.I would also talk to an HVAC person because I believe they can also put a device to cycle the heat a few times a day or even put a secondary thermostat in the apt to take care of the minimum issues.I feel for you because otherwise you have a great tenant.

Most sellers only care if you close so you can usually use another form of capital stack other than what is on the agreement, however, the seller can force you to use the originally agreed-upon payment method. 

Owner shouldn't care about your DTI.

The IRS doesn't care which of you is on title.

You can wind up with title issues if you are not careful. 

It's a fairly unregulated space (charging grandma $750 to puts around for 3 hours, after moving the old box from the horizontal sensor, which was the only problem with the garage door to begin with), so some combination of carefully reading reviews (you have to actually read them to make sure it's not 200 fake reviews), and maybe not giving them the full contract all at once, is in order. 

I would be very careful, especially not having any sort of licensing and promoting these products on a public forum.