Sarah, while I have no desire to be argumentative, I don't fully understand some of your comments. Fanny fall for the wiles of Henry Crawford? A large part of the book is about her not falling for his wiles, no matter how much everyone encourages her, because she knows very well that he is, in your verbage, a user. She is the only one still at Mansfield who does realize it, because she watched his interactions with her cousins and saw how he was using and manipulating him. Yes, Austen inserts a comment about how she doesn't imagine even Fanny capable of withstanding Henry's sustained charms forever, had she not had another guard on her heart, but that's a comment on how powerful those charms are, not a criticism of Fanny's intelligence or strength of mind.
She is pliant, when not asked to do something that goes completely against her principles, but her desire for praise and recognition is pretty modest, and sort of comes out despite herself. She doesn't have a high opinion of most of the people in the group, and logically disdains the good opinion of many of them, but they're all she has, and she can't help feeling lonely and sometimes wishing, again despite herself, to gain some sort of praise of approval. I think that just makes her human, not the naiive fool you seem to make her out to be. In some ways, Fanny is the shrewdest person at Mansfield Park.
She is pliant, when not asked to do something that goes completely against her principles, but her desire for praise and recognition is pretty modest, and sort of comes out despite herself. She doesn't have a high opinion of most of the people in the group, and logically disdains the good opinion of many of them, but they're all she has, and she can't help feeling lonely and sometimes wishing, again despite herself, to gain some sort of praise of approval. I think that just makes her human, not the naiive fool you seem to make her out to be. In some ways, Fanny is the shrewdest person at Mansfield Park.