Farzana is a comparatively minor character in The Kite Runner. She is described as a gentle, courteous woman, who idolizes her husband, Hassan, and is a loving mother to Sohrab. Before Sohrab, she has a stillborn child, an event which traumatizes her deeply.
There are no characters in The Thorn Birds who are particularly similar to Farzana. Perhaps the closest is Fiona Cleary, because of her passivity and silence, the tragedies in her life, and the fact that she is defined by her role as a wife and mother. The polar opposite of Farzana is Mary Carson, who is powerful, manipulative, and exerts a malign influence on those around her.
In A Thousand Splendid Suns, the character who is most similar to Farzana is Fariba, another minor character. She is depicted as kind and happy by nature, but also has to endure a life scarred by tragedy, most importantly the deaths of her two sons, Noor and Ahmad. The character who comes closest to being the polar opposite of Farzana is Laila. Although Laila is not malevolent, as Mary Carson is, she is self-centered and willful, the opposite of Farzana's temperament. She is also an active agent, taking charge of her own fate, while Farzana remains passive.