There is no minimum number of employees before you are required to pay overtime for hours worked over 40 per week. Workers compensation is not required in Texas in most cases. Check www.tdi.texas.gov for more information on worker's comp in Texas.
This information has been provided for informational purposes only. It does not constitute legal advice. The receipt of this information does not establish an attorney client privilege. Proper legal advice can only be given upon consideration of all the relevant facts and the law. Therefore, you should not act upon any information contained herein without seeking appropriate legal counsel.
Take a look at the Fair Labor Standards Act (federal law), that regulates in part overtime for certain type of employees. It is a common way to recover overtime from employers.
You may want to check out the Texas Workforce Commission (TWC) website--you should be able to get the employer information you need from the TWC in most circumstances.
This answer is offered as a public service for general information only and should not be relied upon as legal advice.