The biggest thing with 5+ units is everything is more expensive, and the inspection requirements (depending on the municipality) are often more rigorous.

Life and business are complicated.

Would that lower our tax liability from other income we receive or no because this is purely RE and not an operating business?

Assessments are dependent on what they were for.

In the last 2 months I was receiving a lot of deals in my email account and I received a "great deal" from a small wholesaler; 2 hours later the same property address showed up in an email from one of the "big wholesale companies" 10k dollars more expensive... the property was gone even before I could call the small wholesaler.I believe both are useful and all of us need to make a living, so I understand their role in this business.

.- why would an owner want to do business with someone NOT properly licensed?

In return for excellent service I'll be offering repeat business and I'll happily provide referrals to my existing investor network for those top performers. 

In addition to real estate, I’m passionate about entrepreneurship and business development.

I still have a hard time understanding how this business model works for them, but perhaps that upfront fee covers for lack of deal flow (?) 

Working in a busy property management company, I'm often asked for advice on camera and alarm systems, and in rougher neighborhoods sometimes it can be a toss-up on whether to keep a property boarded-up between showings.