Many houses and duplexes that have been fully redone as well as some that are still owner occupied that will get redone when purchased.

-New, affordable duplexes that have 2 bedrooms in each unit?

@Jose Botello I live in one side of a duplex.

Based on what we're seeing, Dallas seems slightly favorable to SATX for LTR, which we are considering SFH or a duplex.   

-buy OOS duplex and live in one and fix it to rent Airbnb, while the other unit is being rented out.

Based on the value of a property you can likely get away with a inexpensive desk top study such as condos and you will require a more comprehensive engineering study for larger properties like a 4plex.Desktop / modeling options are sometimes good for smaller residential like you mention. 

You don’t want small condos that are easily carbon-copy for example as you have no way to stand out from competition and it becomes a race to the bottom.

For sfh, duplexes and smaller properties its 100% to the broker. 

Wrapping up renovations on one side of my first duplex and I closed in July.

Quote from @Algerson Andre: Hello Everyone - I own property in Buffalo,NY that sits on a big lot that has the potential to serve as ground for a New construction duplex to be built.