Rasheed is more similar to Luke O'Neil than Mary Carson.
In The Thorn Birds, Luke O'Neil becomes the husband of the story's central female character, Meggie, whereas in A Thousand Splendid Suns, Rasheed marries both central female characters, Meriam and Laila.
Mary Carson, on the other hand, while evil, shares none of the motivations of the two men.
For both Luke and Rasheed, marriage is merely a practical move rather than a romantic one. Neither man is truly concerned for the physical or emotional wellbeing of the women they took to wife, and the wives suffer immeasurably because of this.
Therefore, it's without question that Rasheed is much more like Luke O'Neil than Mary Carson.