He also built the 2 story building add on.

If you use any kind of PM software, they usually will have a tenant screening software as an add on feature.

You can get curtains that will meet the spec, but they're enough money that it would be cheaper to do drywall or paneling at that point.The company that did my sump pump had an add-on offer (which I didn't take up) to install fiberglass reinforced plastic (FRP) panels on the inside of the walls. 

The quality of neighborhood, rehab and tenants is top notch, good enough for you personally should be good enough for a passive investor.Brant - Add one more revenue stream to that by negotiating with the management company to compensate you - even a small amount - as you transfer high quality renovated properties with good tenants in place.  

Let me ask you think: 30 years from now, or 23 years from now (if you add one extra mortgage payment a year, every year to your payments, your property will be payed off in 23 years), would you prefer to own 200K or 400K property paid off and would you prefer to get a $2000 cash flow (rent on single family home after mtg paid off) or $5000 cash flow?

I wouldn't add one.

Let me add one. 

Without knowing the details I can not suggest which would be right to add on. 

Others have provided good responses so I'll just add one piece.

Most homeowner policies now exclude mold coverage or you have to buy it as an add-on.