This guy did substantially more than the typical agent would, or even had the skills to do, to make a deal happen.What bothers me James is you jump to the conclusion that the OP somehow took advantage of the seller.

Sounds like you've got a good background and support for starting out as a landlord -- those practical skills come in handy.

Looks to me like you are combining your skills and passions to make the world a better place, and I applaud you for that!  

Actually @Ann North, an architect is more likely to have the skills and experience to know if a lot is buildable.

If you have the skill set to operate strictly as a business you may be OK otherwise don't do it.

Many buyers are unwilling to wait that long and so the pool of buyers is not as large for short sales as for traditional home sales. 

Based on your skills and what you did with your current home, I'd use a similar approach where you have a  building with more than one unit and that needs a bit of work. 

Life skills are sometimes best learned doing dirty jobs that suck well.

You might be confident enough in your valuation skills to forgo an appraisal.

My biggest concern is my rehab cost (that is my next skill to sharpen) and my ARV estimate.