Individual identity vs. social expectation
Edna's entire arc is a collision between who she is and who Creole society needs her to be. Every act of rebellion, from skipping her reception day to moving out, is Edna insisting her inner life is real and worth protecting.
The body as a site of freedom
Chopin uses Edna's physical experiences, swimming, painting, the affair with Arobin, to show that Edna's awakening is not just intellectual. Her body is where she first feels autonomous, and the novel ends in water.
Motherhood as a trap
Edna loves her children but refuses to lose herself in them the way Adèle does. Chopin distinguishes between loving your children and erasing yourself for them. Edna can do the first but not the second.
The limits of romantic love
Edna doesn't find salvation in Robert. His love comes with the same social conditions she's trying to escape. The novel shows that romantic love, as it exists in this society, can't give Edna what she needs.
Art and solitude as alternatives
Mademoiselle Reisz lives alone, plays piano with fierce independence, and answers to no one. She's not happy exactly, but she's whole. Edna's growing commitment to painting points toward this path, though Edna never fully reaches it.