I do plan on using a CPA to file my taxes (first time.... always have done my own in the past but 2018 was first year owning rental properties), but I like to have my ducks in a row, so to speak, by being well organized BEFORE engaging the CPA.'

not much unless your a slumlord.. but anyone can sue anyone.. most tenants don't have the money to engage in litigation.

I purchased a whole bunch of real estate books to learn all the basics so I can engage intelligently in real estate related conversations and plan to join a local meetup group today. 

My advice would be to engage a property management company that specializes in section 8 and not handle on your own.

I'd be engaged in lawful insider trading on Wall Street...

The application for the "C Corp" says if the entity engages in any business requiring a license, proof of license must be submitted.

One has to have an in-depth knowledge of what one is engaging in.What are the high-demand neighborhoods?

If you master these, your business will grow and you will create a loyal audience, because you understand why your audience follows you and engages with you. 

Did you have any prior knowledge before engaging into your first transaction?

Flipping is a business, and when a tax-exempt entity engages in a business on a regular or repeated basis, then taxation known as UBIT applies.