Hazard crew because asbestos mats were thrown on the floor of entry doors?

It will take a haz-mat team to bring your units back to rentable, healthy condition.  

That seller knows what he purchased it for and wouldn't take a loss that big unless they are really strapped for cash.Also be wary of lot rents.

Coffee shop, laundry mat, pharmacy etc

If you are going to be strapped for funds, wholesaling is a good way to get started with little capital.

We did attempt to do a final walk through but the tenants left the house unlocked with keys under the mat.

Originally it was designed as a stimulus for  cash strapped farmers or owners of significant large assets but no cash to exchange for other farmland etc without having to pay tax on the process for which there was no cash being generated.  

@Peter Bowen my comment about 90's construction pretains to the low quality material and minimum standards of the time, much of what we would expect to last 30-50 years would be at 20 and look ok, but really be at the end of its useful life, also back then it was common to not sheet the exterior with OSB or plywood, code allowed corner to corner straps made of thin metal, you could literally cut though a wall with a utility knife in 30 seconds. these methods are starting to show issues now that time has passed.  

@Mike Hoffmanfman Do not dive in the deep end when learning to swim.Also, save your bullets until you see the whites of their eyes.You said you are a Newbie - why tie yourself up with debt at the beginning of the race - like having a ball and chain strapped to your ankle.

@Jose Moll I would post flyers at places where you might find renters, like a laundry mat.