When Joanna takes Fred out for a walk, Walter calls the members of the men's association to check out the layout of the master bedroom. Among those who come to the house are Ed Wimpiris and the Reverend. We cut to Joanna on her walk outside the men's association building where a local police officer warns her about walking around at night, and Joanna heads home. Moments after she departs the frame, a car pulls out of the driveway driven by Ed Wimpiris with the Reverend as a passenger. Ed is shown to be a stunned, sweaty mess and the Reverend suggests letting him drive the car instead as Ed is "In no fit shape", the implication being Ed had taken his wife Charmaine to be "changed" that evening. Unless Ed and the Reverend had Stepford doubles of their own running around or Joanna was in the habit of walking Fred for hours on end, this would indicate they were in two places at once that evening.
When Joanna discovers her "replacement," the "replacement" Joanna has significantly larger breasts than the "original" Joanna, and the camera dwells on her chest to emphasize this fact. In the subsequent supermarket scene, the "replacement" Joanna is back to having small breasts.
As the Eberharts enter Stepford for the first time riding in their station wagon, Joanna's head scarf disappears and reappears several times as the scenes change.
When Joanna has first moved into Stepford she is relaxing on the couch holding a drink. Between shots, her drink changes from dark to light color, and the glass from half full to full.
In the end, when Joanna returns to her home to get the children to escape Stepford, it is dark out. When confronted by her husband, she runs upstairs to her room, the hall is lit by daylight.