What are some examples of foreshadowing in the story "Charles"?

Shirley Jackson's classic short story "Charles" first appeared in Mademoiselle in 1948 and contains many examples of foreshadowing. 
The story is told in the first person point of view of the mother of a boy named Laurie, who is just beginning kindergarten. Laurie comes home from kindergarten every day with stories of the awful things his classmate, Charles, has done. His parents are appalled by the influence of Charles and worry that it will affect Laurie negatively. The irony is that at the end of the story, Laurie's parents discover there is no boy named Charles in Laurie's kindergarten class. A close look at the foreshadowing in this story reveals that Charles was invented by Laurie as a scapegoat for his own heinous actions.
The first example of foreshadowing is the manner in which Laurie returns from his first day of kindergarten. Jackson describes the scene when Laurie comes home from his first day of kindergarten, slams the door, throws his cap on the floor, and shouts "Isn't anybody here?" Laurie proceeds to speak rudely to his father and spill his sister's milk. This suggests that Laurie has changed from the sweet preschooler his mother describes in the first paragraph.
The next example of foreshadowing is when Laurie, after telling the story of Charles' spanking, slides off his chair, takes a cookie and walks off when his father is still talking to him.  
Another example of foreshadowing occurs when Laurie comes home with another story about Charles and tell his father: "Look up....look down, look at my thumb, gee you're dumb." He then laughs "insanely." 
After this, Laurie once again comes home with a story about Charles and says to his father "Hi, Pop, y'old dust mop." By this time, Laurie's parents are so involved in the stories about Charles they appear not to notice the insolent behavior of their son. 
When the mother describes a confusing positive change in Charles' behavior, the father tells her to wait and see if there is really a change, saying "When you've got a Charles to deal with, this may mean he's only plotting." This foreshadows the pinnacle of Charles' deviant behavior, who tells a girl to say a naughty word, and a few days later, says the naughty word in class himself.