I would want to draw attention to the way in which the names emphasises the role of ancestral repetition in this story. In many ways, the problems that exist between the Earnshaws and the Lintons are "inherited" by the younger Catherine, Linton and Hareton. The similarity of their names reinforces this.
If you were to write a feminist criticism of Wuthering Heights, this is an interesting choice. Consider beginning with characterization of each Catherine. Look up the meaning of the name Catherine. Here is a useful link:
Your discussion post is a bit confusing. Are you writing a paper over the two Catherines in the novel and the significance of their having the same name? If so, and I'm only guessing here, then your paper would fall into the three sections you mention: summary, analysis, and assessment. First, you would summarize by establishing the identities of the two Catherines and the role each of them plays in the novel. Next, you could analyze how the two Catherines are similar and different from each other. Finally, you could assess the significance of their having the same name--what does this bring to the novel? Would the novel have been strengthened or weakened if Cathy's daughter had been given a different name? Authors choose their characters' names very carefully, so it is not by accident there are two Catherines in Wuthering Heights. Why might that be?