If this is a multi-paragraph assignment, I would choose three fairly broad topics to deal with. Here are some examples:
How are Maudie and Alexandra similar or different when it comes to their views on Atticus and the trial?
How are they similar or different when it comes to their beliefs about dealing with/raising children?
How are they similiar/different when it comes to their feelings about family and social class?
Miss Maudie is sort of a female Atticus. A strong-minded widow who has chosen not to remarry, she is loyal, trusting and has a liberal view on most matters. Aunt Alexandra is overbearing and bossy and is most concerned with social status and appearances. She believes she will provide better parenting for Jem and Scout than Calpurnia or Atticus, but her own children and grandchildren have not turned out well.