Themes-
1) Supernatural love- Heathcliff’s love for Catherine seems to rise to a different plane, from powerful love to something supernatural. First, he seems to know already when she dies, and then he wishes for a life of torment rather than to be separated from her.
2) Eternal love- Heathcliff plead for a life of torment rather than being separated from Catherine after her death. It reflects his desparation for eternal union with her.
3) Contrast in characters- Another contrast with Heathcliff. While Edgar eventually succumbs to exhaustion, as any normal person would, Heathcliff never does any such thing and he remains unbravery in his grief and determination.
4) Combined locks of hair- The combined locks of hair mark the two sides of Catherine’s personality, the natural and the civilized.
5) Mistreatment of women- Hindley does not attend Catherine’s funeral, though he is invited. Isabella is not invited.Once again, Isabella is treated terribly.
And then write the significance of chapter-16.
https://www.litcharts.com/lit/wuthering-heights/chapter-16