Satire does not depend upon stereotypes but rather upon freely drawn caricatures of realistic characters. This is one place where satire derives it's humor.
Lady Bracknell: married a wealthy Lord when she was penniless and rose to abundantly fulfill her role. Her name is ironically a location name associated with a "lost village." She perfectly illustrates and satirizes the society Lady of the period.
Gwendolyn: the romantic and opinionated daughter of a high society family who puts her faith in platitudes that she nor anyone else knows the meaning of. She perfectly illustrates and satirizes proud narrow minded but pleasant society young women.
Celia: a romantic dreamer who wishes to reform and do good. Another perfect illustration and satire.
Miss Prism: not realistic but a perfect satire upon the wave of women wishing to make their fortunes as authors of romance. This is a stereotype of the useless governess, happily, a rarity.