There may be more opportunities to offset the interest by reducing my auto loan interest rate, home insurance, etc.. if I can wipe out the negative files. 

Most of these tenants have set up auto payments with their bank. 

I was a mechanic at my previous job so I am certain that I can pick up on the nuances of rehabbing fairly quickly.

Does this increase in subprime auto defaults signal warning signs for housing? 

A lot of property purchasors in 2007 and today can be likened to the type of individual who takes on irresponsible credit card, auto, and student debt. 

Looking for new credit can equate with higher risk, but most Credit Scores are not affected by multiple inquiries from auto, mortgage or student loan lenders within a short period of time.

I'm happy to set you up on an auto MLS search if you like so you'll at least be notified asap when good ones pop up. 

Im not looking to make a Million dollars per year, I just want to be comfortable, if my passive can net 6 figures and a lots of equity, Im ok with that, I dont desire a big house (had the house wasnt worth the work for me)  or expensive cars (my previous life i was a mechanic I HATE CARS)  I enjoy being a miser that doesnt need to be a miser, my wife and i often giggle about the people living like they are rich, having to go to a big job everyday, while we go out to breakfast on a Tuesday after dropping our children off at school. 

Lenders fear mechanics liens.I know of a couple of lenders that will lend 100% of the construction costs. 

You mentioned all but one is rented, What's the condition of the interior, exterior, and mechanicals?