I live in Arizona, so school itself isn't that expensive (abt $400), which leaves the exam and any licensing fees.

It still seems like I could roughly break even on some of these properties, taking into account mortgage, property taxes, PMI, expenses, vacancies, etc., and I'd certainly benefit from the relevant tax incentives and would be earning equity, which is great—but is that enough?

So yes, this will cut your expenses for routine maintenance.

I love Portland and understand their sales prices relative to the rest of the country.When I flip, I like to look for a min 35% return on my capital after expenses.

It's not that expensive.  

DC is an expensive market to start in.  

Frank used lot rent (not home rent) and used 40% expense ratio (0.6) which gives a reasonably low offer price.  

The current landlord has minimum expenses, and is treating the billboard as traditional commercial real estate evaluation.

I live in the very expensive Brooklyn/NYC market.

That makes your self-directed IRA investment passive (as it must be, under IRS regulations) but also lets your LLC handle the management expenses and receive a management fee to augment cash flows.