In Hills Like White Elephants, are both characters static, and is there indirect characterization?
Well, no, I can't confirm the first element. The characters weren't fully static. There was a decision reached in the story—to have an abortion—and this will reshape both of them, especially the woman, and their relationship.
There was, however, considerable indirect characterization in the story. Hemingway characterizes the two characters by what they say, the pacing, what they don't say, how they interact, descriptions of the landscape, etc.