Little Edie's black bathing suit with yellow flowers is not a reproduction. It's a vintage piece from the same batch as the suit Miss Beal owned. It belongs to a fan of the original documentary, who lent to the film's production crew for the shoot.
As pianist and music teacher George "Gould" Strong, Malcolm Gets's costume includes a diamond ring. It's actually the ring Edith Beale gave Strong in real life. Strong's relatives lent the ring to the film's production crew.
In New York, Little Edie lives in the Barbizon Hotel, an apartment building on East 63rd Street for young single women. In one scene, Little Edie sneaks Cap into her room because of the Barbizon's strict ban on male visitors. Parents often choose the Barbizon for their daughters in the city for that reason. Other famous women who lived at the Barbizon while starting out in New York City include Joan Crawford, Grace Kelly, Candice Bergen, and author Sylvia Plath, whose protagonist in 'The Bell Jar' lived in a place much like the Barbizon.