Ugh.In all seriousness, I think for $50,000 with a 1200 square foot house in Michigan should be able to modest rehab.

Because of the relationship between lower housing prices back in those years, and how rents have increased since, we have good cash flow on our portfolio.  

I would like to sell a couple properties in the future, would I be able to use the 1031 strategy to buy one house that I would use as a primary residence?

If you don't/won't have WiFi then you should either consider a SimpliSafe system that you can move around from house to house, or some type of Trail cameras like hunters use for identifying game areas.

We all assume this isn’t a house you’d buy with your own money.

I currently have a 4/2 SFH/LTR/Section 8 house under contract and I am getting quotes for property insurance.

We then purchased 2 houses for investment purposes.

Lots of older houses but there seem to be several that have the potential for cash flow and while not exactly modern on the outside, have been renovated inside. 

Rents have been pretty close to what the housing authorities advertise, sometimes even a bit higher.Fort Wayne’s a solid spot with low taxes and good cash flow—definitely worth looking into.

He'll still be renting - just from you instead of others, and at all the costs to you that you have enumerated.Your son doesn't "need" to buy a house.