I am actually doing this right now.

The installer may not have left enough room for expansion gaps.

My plan is to essentially by up the scrap lots left in newer subdivision neighborhoods by big developers, build sub 2,000 sqf single family homes, and market them between 200,000$ and 300,000$.

We have decided that that is the right direction to take  appreciate the advice.

I sold all my NPL's in NY and I felt such a relief.1 & 3 not so much as a surprise to me, a lot of training going on right now on that front so gurus raking in the cash. 

That's not how proof works.Am I legally in the right to cancel the contract for breach of contract in a day as soon as I get this last lease-up fee if he doesn't pay the deposit?

Those are good hacks to get better options than what you might get here, looking in a particular area.You have the right idea though, you want to give some sweat equity first or gopher skills.

Right now, I'm just looking at Detroit itself.

How old are they/how much life-span is left, what's replacement costs for that today, then forward cast it, take into account inflation to such costs, now you have your total and a date.

Also when I find the right property for my wife and I to use for part of the year we will turn it into a mid term rental for the other 6-9 months of the year.