] A footnote in my copy of NA says Alice was probably Eleanor's maid. Does this sound reasonable to you?

My edition of NA has a similar footnote. However, even when I read that, I thought it far more likely that this 'Alice' was the daughter of the home where they would be visiting than Eleanor's maid.

On the other hand, the fact that Eleanor calls her by her Christian name and not Miss Longtown or some formal title maybe does mean that it is a person of lesser status. And we do know that Eleanor has her own lady's maid who has also met Catherine during the visit to Northanger.