So, you just have to shop around and select products that work for you.One other thing I suspect is going on is that your option B is a conventional Fannie/Freddie loan product not a commercial loan.

The math only works if I select my property right.

A more effective method is to read and attend various networking events. 

I have used them before for one of my duplexes, bought a washer and dryer, they have a good selection and I have no complaints.

I believe I need to get pre-qualified once more now that my financial situation has changed, so I'd like to ask all of you - How do you find and effectively vet mortgage brokers in your area?

If it was possible to do a targeted mail campaign directed to a potential Seller you know something about, even general demographics, that might have a special effect. 

You can't mix and match.At that gross revenue level, it's very possible an S election and/or a Solo 401k make sense. 

I would like to know some good books or effective ways of educating yourself without going to the gurus.

You are correct as inventory is increasing, and will effect the supply/demand equation.

I couldn't give you a simple answer that would help you- you've gotta build your own recipe.Overall: Efficient but effective marketing.