Why Two Catherines?

I think there were a few reasons Bronte decided to have both women named Catherine. First of all, I think it was to add irony because the first Catherine went from being an Earnshaw to being a Linton and the second was a Linton and later becomes an Earnshaw. Secondly, they both were strong and independent women. Lastly, they both were associated with Edgar Linton, who was hated by Heathcliff. Here is a picture of Edgar Linton: