Like do some cleaning job, contacting maintenance people, knowing how to pay water bills etc. these are all the basic work when you become a landlord and you need to know how to manage your property first.

Near outdoor activities, good food and some kind of water.

Do you have insurance for your appliances, if the tenant says the washer stopped draining the water and now their clothes smell like mildew, do you know how to schedule service with warranty or call an appliance tech?

The yard alone is approx 10,000 squarefeet , watering the lawn will significantly increase the water bill.

If the house still has 60 amp service that tells me its old , so the water line is probaly old . 

They had a track record of completing work, multiple crews, standard materials, and refinancing successfully.

The loan caps vary across lenders, across experience buckets, across asset valuations but 70% - 75% is standard.9mo note at 12.99 i/o - Most say "12" months and then bake in a fee if it goes longer than 9 months.  12.99 is high. 

That way any water heater, furnace/boiler, etc are covered by that insurance policy. 

Unfortunately, many owners & PMCs maintain Class C & D properties to Class A & B standards. 

With standard ceilings, and single-story I would expect to spend about $100k for basic turnkey on that addition with a hungry builder.