Would you suggest to have a therapist speak with the children before going to court for child custody?

As to your first question, I cannot say without more information about your situation. As to the second question, again I don't know what you mean by a third party. Not knowing much about what is going on in your case, or the ages of your children, you may want to ask the child custody recommending counselor (i.e. the in-court mediator) to interview your children.  The mediator can then take the children's input into consideration in making her custody and parenting recommendations. I hope this helps you.