Mac Dade Blvd and Chester Pike were never great, but now you've got tattoo parlors (nothing wrong with tattoos) and vape shops on these roads and many of the duplexes are near these locations.  

There are never enough clean rentals in the area, and you can also build an Accessory Dwelling Unit on almost any lot which will also provide you with additional income.

To subdivide down to the minimum 1.5 acres or keep it to 3-5 acre properties and go with a higher end single family builds with detached garage above accessory dwellings.

Also, I am wondering why, assuming you will live in one half of the Duplex, if you considered getting an Accessory License to do an STR (vacation rental).

Suburbs in Texas generally all have similar zoning restrictions on accessory units. 

You want to make sure your zoning allows an accessory unit and/or a two-family dwelling first. the fist link is the zoning map and the second is the zoning code.

If you are in Davidson County, you either have to build them on land that is zoned for mobile home use (and they would need to be mobile - not permanent foundations), or you'd have to build them as an accessory dwellings to an already existing structure (i.e., on land with a dwelling already that is zoned for multiple dwellings).I talked to codes about this because I wanted to build one on my lot (.25 acre with a SFR on it) but the zoning is RS10.

If it is zoned for a duplex or AUD (Accessory  Dwelling Unit, i.e. mother-in-law unit) You will have to get Permits and bring it up to todays codes.  

One thing to check though is see what the house is zone for or if the allow an accessory dwelling unit if your going to use it as a duplex  or multifamily. 

NH is passing a new law next year, in June of 2017, making it legal to rent accessory apartments in your home to people other than family members.