I think that you have sketched out some very good points here. Indeed, self deception is a powerfully resonant theme in Styron's work. Sophie's character has been built on deception in order to survive. In Auschwitz, she attempts to use guile and deception to garner favors in the camp with Hoss, as well as the attempt to put her son in the Lebensborn program. Her pathology of self- deception ends up sustaining her faith that her son will wind up surviving. Additionally, she deceives herself in the understanding of her father, which in her mind is not one of contempt, but rather represents a misunderstood force who was caught up in the wave of Nazism. Naturally, her post Auschwitz life is one of deception. She deceives those around her in suggesting her father was a great man, as well as her faith in Nathan. She obviously knows that he is abusive and unstable, but her own sensibilities have been so damaged through her experiences that she deceives herself in believing that she can change him or that he is capable of changing. In a larger sense, one can also see her self deception extending to her attitudes towards Jewish individuals and minorities after the war, and her stand on evil, in general. Some would argue that she deceives herself in the notion of the choice she had. Indeed, having to choose which child was to live and die was not a real choice. Both were condemned to die, along with the mllions of others at Auschwitz. However, the blurring of the lines in deception of others and deception of oneself became so brutal for her that Sophie ends up internalizing the guilt of the decision, seeing herself as simultaneous victim and aggressor and not knowing which classification is closer to "the truth."
Indeed, Sophie does find it easier to deceive others. Yet, in the final analysis, the psychology of deceit, in terms of deceiving others and deceiving herself, proves to grab hold of her psyche, and plays the decisive role in entering into her suicide pact with Nathan. In this act might lie the only shard of truth in an existence predicated upon deceit. Sophie does find it easier to deceive others as well as herself, yet it is the latter whose unavoidable presence does the greatest of harm to her.