Phoebe is sitting in the lotus pose (padmasana).
Salinger admired F. Scott Fitzgerald, who attempted a career in Hollywood but couldn't alter his writing style to suit movie scripts. Salinger himself also had trouble with a Hollywood adaptation of his short story "Uncle Wiggly in Connecticut" (renamed "My Foolish Heart"). Holden's views on Hollywood reflect Salinger's views.
Wilhelm Stekel is the second psychoanalyst and disciple of Freud that Salinger includes in The Catcher in the Rye (the other being Alfred Adler).
That Stekel's most famous work was a book on sexual fetish, and that he died by suicide (at age 74), may be relevant to Salinger's themes. Stekel also pioneered the idea of short-term analysis, which he called "active analysis," a precursor to contemporary counselling and therapy.
New York City's famous Fifth Avenue Christmas windows: