In Kathryn Stockett's The Help, the three main characters have strengths and weaknesses.
Skeeter Phalen's strength is her resolve in wanting to expose the often difficult lives of black maids working in white households in Jackson, Mississippi. Her weakness, at least at the beginning, is that she has no concept of what the life of a domestic worker is really like, and equally has no concept of what dangers she and the others are in by exposing how poorly many of the maids in the novel are treated.
Minny's strengths and weaknesses are easy to spot. She admits that she cannot keep her mouth shut, and has been fired from numerous jobs because of it. Ironically, this may be a strength of character in some form, for it is her inability to pretend and play the game that the whites want her to play by "yes, ma'am-ing" them when their demands are poorly planned or idiotic. It is her honesty that might be seen as a strength. However, the one that most stands out for me is Minny's courage. Regardless of what she is feeling, she puts herself out to protect others. We see this when she insists that her "Terrible Awful" is put in the book: it exposes her to danger, but protects the other maids who have placed their stories in the book as well.
Aibileen's strength is easy to find when we see how much she cares for the seventeen children she has raised during her career, as shown in the way she is raising Mae Mobley. She has loved these children as if they were her own. Aibileen is also extremely bright, a peacemaker and a realist. She is brave and supportive of others, as we see in her friendship with Minny. Finding a weakness for Aibileen is much more difficult. Perhaps her weakness is giving so much of her heart to the children of folks who will retrain the children in their own image (bigoted, inflexible, catty, etc.) when they no longer need Aibileen.