In The Awakening, how are the minor characters (e.g. the lady in black) significant to Edna's story?

These minor characters all serve to contrast with Edna and
her struggles with her own identity and place in society.  The young lovers are a stark
contrast to the marriage of Edna and Leonce, at least as Edna perceives her marriage. 
The young lovers are described as walking shoulder to shoulder, suggesting they are
equals and connected.  Edna does not feel this with Leonce, who takes their roles in a
more traditional way and has strict expectations for how Edna will behave in their
marriage.  She is to wake with the sick child; she will act as this society expects of
her.  The lady in black is likely an old widow who is now living out the end of her life
in the expected way.  She wears the color of mourning and serves as a visible picture of
what the last phase of what life is like in this society.  It is important that the
young lovers and the lady in black are both mentioned in the same paragraph.  This
suggests that the young lovers may be innocently unaware, but death is always following
people through life -- it is the inevitable end to everything.