My son currently lives in the townhouse b/c he is going to school and works in the area.Since he is young and starting out in life, I would like for him to only cover the basic costs (taxes, HOA, utilities) just enough for me to break even (I believe that will put him slightly little lower than market rent rates). 

Their a/c starting leaking and has missing ductwork, and is blowing air in random places.

Dollar Stores often instead of renewing the lease get sucked away to developers promising to build them Dollar Plus stores with upgraded construction for slight rental increases.Especially is absolute NNN lease the DG could jump ship to a brand new building and avoid tons of TI costs they are on the hook for with older building ( parking lot, roof, A/C, etc.)Professional tenants with thousands of locations tend not to be dummies.

But I tend toward more Class C than B.   

Most do a LLC but again it can be very different - for example I have a C corporation, had a S corp, had a LLC etc. and each one for very unique and different situations. 

I have no idea how real these rates are they dont have credit score just A+,B+ , C+ d and e and application fee is $400.

Having said that, I am a bit concerned as it relates to the overall market, especially in class C properties and most especially class C properties in border states. 

Please stop asking us for "the best" zip codes to invest in.Detroit has around 183 Residential Neighborhoods - wouldn't it be nice if "some proprety mangagement company" Classified them all as A, B, C, or D on an interactive map that real estate investors could use to make better decisions?

Yes, you can go visit Class C & D tenants at their homes to convince them to sign up for auto-pay, but:1) Once you leave they will revert2) Their biggest problem is NSFs! 

You are correct in your assumption that it will impact how low they can go on the down payment, though, b/c commissions will need to be paid out of closing costs.