Actually, Sally Field has some of the facial structure of Mrs. Lincoln. I would think they would be able to make her up to play the role quite well.
She would have to pack on thirty pounds to look like Mrs Lincoln. It made me grind my teeth to watch someone as skinny as Mary Tyler Moore as Mary Todd. Neeson also has the wrong buold for Lincoln. The actor I liked best in the role of Lincoln was Henry Fonda. Although they had to put heavy make-up to make him like like Lincoln in the face. Fonda had about the right build, had the same shambling walk, and even managed Lincoln’s tenor voice.