] Anyone have any idea why JA spelled the name "Eleanor" in Northanger Abbey and "Elinor" in Sense and Sensibility? Are they different family names/spellings?

Why Jane used these variants of the same name we can't know of course. I suppose she liked them. Perhaps someone remembers if ther is any of her relatives or friends who had such a name?

Here's some info you may find interesting.
ELEANOR female English
Pronounced: EL-en-or
French form of the Provençal name Alienor, which is most likely a Germanic name of unknown meaning, though it is possibly a form of HELEN(Greek?). This name was borne by Eleanor of Aquitaine (12th century), the wife of both Louis VII, the king of France, and Henry II, the king of England.

ELINOR female English
Variant of ELEANOR

Other variants:
Alenor, Aline, Eileen, Elaine, Eleanora, Ellen, Ella, Enora, Helen, Helena, Helene, Lenore, Leonora, Nora, Noreen, Norene, Norina, Norine

Leif G-n