I am representing myself in motion for educational support for my 18 year old daughter, Ex has retained a lawyer. I am concerned about what a judge will permit the lawyer to enter as evidence. I do not want my child to have to testify against her father. Does anyone know what is legally admissible?

Anything that the judge will allow.
The child may be called to testify.
Did the original child support order include education past 18.

In the US each state has its own laws, some do not require it.
So knowing your state law would help

What state are you in? That will make a huge difference being that some don't require support past 18 even if the "child" is going to college.