This episode marks the introduction of Cal Fletcher, Jessica's second cousin once removed through her marriage to Frank.
It seems highly unlikely that someone as conscientious as J. B. Fletcher would make plans to stay in New Orleans the very last night of Mardi Gras (which led to her not having a place to stay upon her arrival) simply for the sake of a vaguely concerned relative. If her cousin, Cal, had not been in contact with the family for three months, one more day should not have mattered.
Lt. Edmond Cavette: Jessica, you are a warm and beautiful woman! You are also stubborn, mule-headed and impossible!
(Introducing herself to Cal.)
Jessica Fletcher: I'm Jessica, your cousin from Maine. Well, sort of. My husband Frank's uncle was your father's cousin, or was it nephew, I'm not quite sure.
Aunt Mildred: I'm very worried about Cal.
Jessica Fletcher: Cal?
Aunt Mildred: Second cousin once removed on Frank's side, Jane and Edward's son. The one who lives in New Orleans and collects butterflies.
Jessica: I don't think I know him.