I'm in the process now of looking into Accessory dwelling units to maximize the duplex and still occupy. 

Also, owners have nice vehicles and spend extra on them like new chrome rims, fully tinted windows, and other dumb accessory stuff.

The backyard has a good space and I intended to put a tiny home / ADU (Accessory dwelling unit) in the back yard.

About 3 months ago, we decided to invest in a house (with rental accessory apartment) in an area where 3 of our kids go to college. 

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.