There is a single family home that was divided and one half has been rented and an ad on small "house" that has also been rented mostly long term.

Anyone can live anywhere they want if they have the money, and sometimes houses are bought and then rented out without much background checking on the people moving in.

I’ve been offering a $100 referral fee for existing tenants who refer a new tenant to any of my properties.

Small multi-family is hot right now due to house-hacking (low barrier of entry), and future cash-flow. 

That's a house of cards ready to fall down fast. 

Property Management takes a nice cut out of your margin, unless you have the systems built to do it in-house. 

If the structure on the property is determined to have no value, be careful when you consider paying the “value of the land”.The value of raw land is different than the value of land with an existing structure, even if the structure has no value.  

If you are newer I'd suggest a house hack unless you can rinse/repeat this process again. 

These areas are experiencing significant development and population growth, driven by families and professionals seeking more affordable housing while staying close to the job hubs in Plano, Frisco, and even parts of North Dallas.

Everything in house.