BP has various tools to help you analyze your deals (rentals, flips, wholesale, etc). : https://www.biggerpockets.com/investment-calculators7.

Does anyone have any experience relying on home warranties to help cover appliances, etc?

If it’s well run, kids are doing their homework and adults are helping with the homework, no problem.

You’ve already paid more in vacancy than they will charge you to run it for you.

You could start by telling us a little more about your current mortgage.

Specifically the tenant needs to be costing you more than the vacancy is going to cost you. 

Once you stabilize and raise the rents it would be the hope that the property would appraise for more and the owner would refi and get back significant returns.

We are on the minimum plan with four rentals and don't see the value in paying $180 a year to collect rents, payout rents more than a week later, and screen tenants when we have turnover. 

Chances are busy builders are going to be charging more?

Any advice would be helpful!