Joan Crawford was never seriously considered for the role of Scarlett O'Hara. Her period film, The Gorgeous Hussy (1936), had just flopped, and it was felt she could not do a period film successfully.
Joan Crawford never had an affair with David O. Selznick.
Joan Crawford never received a car as consolation from David O. Selznick.
In the film, Carole Lombard complains about Scarlett. However, in reality, she had herself put under contract to David O. Selznick in order that she would be considered for the role.