This is an interesting essay assignment.  In each of the stories you list above, the protagonists are women.

Each woman suffers from the roles placed upon women during the given settings of their stories.  All are set in a roughly 20-30 year time period, so the struggles of each of the women are very similar, although one protagonist faced more adversity due to the fact she was an African-American woman.

You would probably do best by providing some background information on the time periods each story is set in and what the roles of women were during those time periods.  I would then tackle the individual struggles each woman faced as it relates to those defined gender roles.  You can use the "Historical Context" section and/or the "Themes" section under each story here on eNotes to help.  For example, the "Themes" section about "Sweat" says this:

Delia’s options are quite limited. Hurston is careful to emphasize that a black washerwoman is not able to clean away the abuse of a philandering and merciless husband while following a strict and meek Christian moral code. As she must work on Sundays (against convention) in order to fulfill the heavy obligations to her white oppressors, Delia eventually finds that she must resort to a conventionally immoral way of dealing with Sykes. (eNotes)