Because you are self servicing your loans most are not legally compliant with consumer protection laws and CFPB requirements such as sending statements on a monthly basis that have all the language the CFPB requires as well as each state may have additional requirements for sending out just a simple statement.

Your parents and you could probably use a really good Elder law atty in NY as well to look at how best to structure their ownership and passing to you.Nothing wrong with selling to a related party and completing a 1031 exchange. 

I'm recently retired after a 30 year career in law enforcement.

For collections in Southern California, try Sutton Law Center or California Judgment Enforcement.

In particular:(1) Should I hire a law firm or collection agency to facilitate the transaction?

Will depend on several factors like the type of property, type of tenants, your risk tolerance, other assets you own, your estate planning, laws where the property is located, etc.

I'm being told that the area will have zoning laws within the next 5 years so I guess it would be who of me to get this thing going.

Non-US citizens can have LLCs in the US which will allow you to have a business in the US, pay taxes, and comply with laws.

Depending on which market you plan to invest, it's also helpful to educate yourself on state restrictions + laws, rental property management etc. before diving in.

I've been house hacking my place (I rent out a 3-bed 2-bath residence and live in a small in-law unit in the back) for just about 3 years and have been setting aside money each month for my reserve fund.