Who is Lizzie Hexam from Our Mutual Friend and what is their importance?

Lizzie Hexam is the daughter of Jesse Hexam and the sister of Charley Hexam. Along with her father, she discovers the body of the man believed to be John Harmon. Both Bradley Headstone and Eugene Wrayburn fall in love with her. After Headstone attacks Wrayburn, Lizzie saves him and marries him.