Without knowing the apartment and its wiring hard to trouble shoot.

Your particular DM "effort" had not been presented previously,  but it's easy to see why it did not work out as others have pointed out.I'm sorry you way overpaid for your list, but most can tell you just one and done isn't going to produce much...what we're talking about is not much like a vending machine; more like farming.

If you wait 6 months, you do not have to produce receipts and payment to contractors for repairs.

You’re going to need to find something transactional to produce the income you will need to do what you want to do.  

I can't even begin to imagine the trouble that landlords get into that start treating their tenants like friends or, worse, romantic relationships.

CONSLower revenue potential vs B & BStill need to get the B & B license (and still need to provide "breakfast" even coffee & donuts)STR biz model would mean much hight taxes vs B & B business (from what I understand)HUGE Airbnb competition - area is highly desirable but oversaturatedPROSGreat revenue for an under $500k total investmentQuicker ramp up to produce revenueCan become passive much sooner than a B & B OPTION 3.

If it was him I would advise her to vacate and not tell him where she moves to as he will be back and cause more trouble.

There ain't no easy way to make a buck.Regarding the sloppy tenant, throw him out, sounds like trouble.

I know we aren't supposed to give specific recommendations on this site so I don't want to get us into trouble.

Dividing that by 2 isn’t likely to produce enough of a return to make it worth anyone’s time.