That's the site I've been using. Here is where I've been reading on changing a child's name.
https://texaslawhelp.org/guide/i-want-to-change-my-childs-name?tab=1
Pushing for the 1st option, "Instructions & Forms for Child Name Change: Both Parents Agree to File Together." If we can get him to sign the forms listed, we all move on and leave it behind us. Kind of expecting the 2nd option, "Instructions and Forms for Child Name Change - One parent filing - Other parent will be served," where I'll have to get lawyers and courts involved and drag this shit out.
I'd like to force his hand with the child support ultimatum, but don't know if that would somehow damage our case should option #2 be our path forward.
Something like, "Apparently you want to take the difficult route. We want to make this easy, but if you refuse to respond we will be seeking 9 years of back child support and also succeed in changing (stepson's) name in court. If you are uncomfortable meeting with me, we have provided a mediator to meet you with the documents to sign. If neither she nor I hear from you by this Friday, we will move forward without you."