The primary requirement is that the expected rent would cover the mortgage on the home - and that expected rent is typically determined by a combination of the appraiser and some service like airdna (a site which determines fair market rent).

The license doesn't cost more, the service and quality does.And a note on that cost, in my experience hiring contractors, only a small percentage of the cost savings was due to finding the right guy who is willing to work for less.

Depreciation begins when the property is placed in service (available for rent).

I do not use a property management service to advertise and have always used Zillow to advertise, previous references, housing records, credit checks etc

Quote from @Patrick Roberts: Echoing what Chris said - use a third party servicer.

The ways around that are to build a business around supporting their voucher and inspection program and spending no small amount of effort ensuring they are smoothly servicing your rentals. 

At our firm (tax advisory) we are offering a service to help clients with this and we expect many tax/cpa/law firms will as well. 

A debt service loan is popular for that step.

So you would spend around $25-$30k a month (this was 15 years ago) on police details and require union gate and non union gate if you had non union workforce as well.In DC area, the utility providers are a huge challenge, whether getting permanent power, or water/sewer service etc - good luck.

Quote from @Dani Murai: Any recommendations for a reputable general contractor that services the Torrance/Gardena area?