I'm attempting to catch-up, so please forgive me if this idea has already been thrown out: It occurs to me that Mrs. Clay is included in these first chapters to show a living example of what could have happened to Anne if she'd married CW without enough money to live on and he was killed in action; "a daughter of Mr. Shepherd, who had returned, after an unprosperous marriage, to her father's house, with the additional burden of two children."