Demand for Midland will always be there, not sure on STR rules but if you're traveling regularly then STR it and get the tax benefits/utility from it but make sure you're not violating the occupancy stays.

Do you regularly work with cash buyers on off market deals?

Even with identical facts.

Attend local meetups regularly.

Do our regular rent increase and then add on an extra $100 or $200 because you have to chase the rent Let the tenant know now that their rent will increase significantly if you have to chase them for the rent every month. 

Backstory:We rent the ADU out regularly via STR or MTR and live in the main house currently and are looking to size up.

This is especially true the finer the market is.I see a lot of different strategies from serial investors I work with regularly, and would be happy to learn more about your finer details as such.

You also have to have a system in place to vet your guest (which Airbnb doesn't do anyway - all they do is "verify" their identity), create a lease agreement, accept deposits and payments and issue refunds of deposits.

Houston isn't making 4 unit buildings regularly.

Also, Z Wave and Zigbee radios are in sleep mode 99% of the time whereas WiFi radios are communicating pretty regularly.