In the short story A&P by John Updike, what is the difference between the 3 characters Sammy, Queenie, and Lengel?

In the short story "A & P," there are, indeed, differences among the characters Mr. Lengel, Sammy, and Queenie.
Mr. Lengel is the manager of the A & P grocery store. He represents the adult who holds conventional views as he enforces the rules regarding attire and conduct in the store. When Sammy feels that he should act on the girls' behalf after Lengel embarrasses them, he tries to convince Sammy not to quit partly because he is a friend of Sammy's parents. He tells Sammy, "You'll feel this for the rest of your life," implying that he should attend to conventional rules.
Sammy is a nineteen-year-old who works at the grocery store. He has assumed a somewhat cynical attitude about the adult women--the "sheep" and "house slaves" as he calls them--who shop there. He is disgusted with them because they seem to have lost any personal pride. For they come to the grocery store in curlers and shorts that display "varicose veins mapping their legs and nobody, including them, could care less." In contrast to these "house slaves," the sight of the young girls in their swimsuits as they enter the store is welcomed by Sammy as a delightful change, as well as one that is sexually enticing. Unfortunately for Sammy, he becomes romantic in his perception after Lengel accosts them, explaining the store policy: "Poor kids, I began to feel sorry for them, they couldn't help it." This romantic perception leads Sammy to believe that his chivalric act of quitting because of Lengel's having embarrassed them will impress the girls. However, when he goes outside the store after quitting and looks around for "my girls," they are already gone. His act has gone unnoticed, and Sammy cannot decide whether he is heroic or merely foolish.   
Queenie is a somewhat brazen teenager who leads two other girls into the store in violation of the dress code because they wear only their bathing suits. Queenie has the straps of her suit pushed off, and she walks slowly, "putting a little deliberate action into it." She is a self-centered girl who apparently likes the attention that her attractive figure brings her until she feels embarrassed and blushes when Lengel informs them of the store's rules. She and the other girls have no interest in Sammy, and they depart before witnessing his act of chivalry on their behalf.