I had to fix damages and clean extensively after she left.

I think you're gonna see a lot of deals underwater trading before year end, with banks trying to clean up their balance sheets.5.5% with 25% down is a very competitive rate.

I run my own small pressure washing/handyman business on the side while I was working full time over the summer doing plumbing and electrical.

And can I get away with only getting permits on new electric & moving plumbing, but demo,  erect walls myself and things like that?

If the ground is clean, they are less likely to litter.

Since electricity and water is included in our rent, we also have a clause stating that if the monthly bill doubles compared to the month-comparable bill from the prior year, then the excess will be assessed as a fee.

I included in the proposal the benefits for the landlords, such as no worries for vacancies, a 5% profit share on top of the rental rate and the provision of a professional cleaning team for their property.

If someone asks if it can sleep 12, I don't charge for that either.I would either just charge the guests more for the cleaning or if you offer free cleaning, add it to the nightly rate.

Long terms rentals will have repairs from time to time, but if it is a true emergency, you are going to be calling someone (eg plumber) to come in and fix something, so that is no different than your own home (minus the clean up). 

If the tenant identifies an area of moisture that may be causing growth we immediately address the source of the moisture, replace and damage building material (usually dry wall) and or use mold cleaning solutions/mold blocking primers as required. good luck