The prices can very wildly that is for sure, but I last saw this cost around 12k. 

If I was a renter and the landlord was didn’t know what they were doing and priced the rent 30% too low do you think I would insist on them raising the rent?

The delay in closing cost me 10's of thousands of dollars and could have easily been avoided. 

Enter the total cost of utility and the number of days the tenant occupied, and the spreadsheet could calculate the total charge.

But personally in my state of WA, I can lend in 2nd position on a rental at very low CLTV and put a 1st on a new acquisition at a low LTV and I would take that loan all day, every day over a 1st position on an acquisition at 85% LTC.

I do have an empty lot next to my current SFH , doing nothing (but costing me money to mow :)) my thought was to build a detached guest cottage to serve as an overflow for guests or it could also serve as a seasonal / monthly rental.

The cost to repair it is close to the net annual income.

You only have 3% vacancy which is pretty low.

Do you have recommendations for low cost options to post a 10 day notice on the property? 

It is quite an undertaking, processes will be long and unforeseen costs could pop up.