This house didn't need major reconstruction, mostly mechanical and cosmetic updates.

You do not need to be a mechanic to own a car.

If all the mechanical systems are good and the units are in decent shape, you can spend most of it on updating your unit to a higher quality apartment that will pull more rent when you vacate. 

I will be all in at about $12k with repairs, so I am really not interested in loosing the money if he decides he wants the repaired property back and wants to start playing games.Could I not place a $12k mechanics lien on the property after repairs which would prevent him from encumbering the property?

There are a few things to watch out for.You need to make sure the mechanicals and structure of the house is good.

What they do not do is fix all the roofs, mechanicals, etc. that will eat up the new buyers in the first 5 years or so of ownership.

I would be concerned that you would be too exposed by having two new properties without a great handle on repair status/major mechanical systems (especially with upstate winters nearby) etc.

I think that would make things clear for people to understand and clearly see the difference between compound and simple interest.I'm interested in more details related to the mechanics of making this happen.  

I'd prefer large complexes but I have a young family and a golf habit that sucks up a lot of free cash that could be saved for a purchase like that.So, I found a 1950s ranch on slab in Colerain Twp (the Northbrook Area for those familiar) that I was able to purchase for $23,500 at auction and was pleased to find a new roof, newer kitchen, new mechanicals, newer bathroom, etc. when I inspected the house.  

Newer roof, mechanicals, stucco w new paint and beautiful woodwork inside.