Build your basics first, like good renters, quick repairs, cash saved, and a clear backup plan.

As you probably already know, but for the sake of the "lurkers" (those who read but don't ask questions or announce their presence) "hi fellers", a special warranty deed basically means the owner (or title company), will take responsibility from the time it is in their hands.

Basically I can start building a portfolio.

What you've stated gives the basics with some of the shortcomings.

Where i come from that's like saying you never learned how to walk, or eat with a fork, it's basic necessary know-how for living.

I suspect your insurance number is low. 35 to 45% all in costs is pretty common if you have 3rd party management. keep in mind cash flow on top of all cost is only one component of the investment and in my mind not always the most important unless your buying in an area that is depressed and you think values will be stagnate for basically the life of the investment then positive cash flow a very important factor. 

The sellers attorney is a short sale/ foreclosure attorney and he seems pretty optimistic that HUD will approve the shortage and basically forgive the $35k short fall and allow the building to close. 

In my work as a Maryland real estate attorney, I see investors using a mix of MLS data, title resources, and basic deal-analysis and property-management tools.

Basically, if you bought real estate anytime from 2010 through covid, you made money because the market was constantly rising.

The main exception seems to be service providers who promise to speed up the learning curve or help investors make money faster, which is almost always unrealistic but taps into basic human nature.