What part did Diana, Betsy, and Brigid play in Lyddie's life?

Diana, Betsy, and Brigid all play important roles in Lyddie's life.  
Diana is really the first to welcome Lyddie to being a factory girl.  Diana takes Lyddie under her wing and teaches Lyddie how to operate within the very busy factory.  Diana is also the woman who first treats Lyddie's injury on the factory floor.  Additionally, Diana secures Lyddie access to a doctor.  Lastly, Diana is the woman that really encourages Lyddie to sign the petition. 
Betsy's main role is that she turns Lyddie toward the importance of education and learning.  Betsy first does this by reading Oliver Twist to Lyddie.  Eventually Lyddie learns that Betsy is working in the factory to put herself through college.  The possibility of that for Lyddie had never really crossed her mind until she met Betsy.  
Lyddie does not like Brigid at first.  Lyddie is forced to help her learn how to work in the factory.  That causes Lyddie's production to fall a bit, and Lyddie isn't happy about that.  Eventually, Lyddie becomes Brigid's protector in the same way that Diana was Lyddie's protector.  Near the end of the book, Lyddie helps Brigid escape from Mr. Marsden's sexual advances.  The incident leads to Lyddie being fired.