You're right - when we first meet her - the author makes sure we know about her sense. And yet, the more we're into the book, the less is said about it! And all of the situations you mentioned would undoubtedly aggravate throwing herself headlong into sensibility!

I wonder if that's one reason why Elinor is hestitant to talk to her and wishes her mother to do so. We know (well - strictly speaking - we [I] assume) that earlier they had fairly intimate conversations with one another. We see, anyway, Marianne asking Elinor straightforward questions and Elinor answering (and the answers being ignored). To me that indicates their relationship was tight and close. I've often wondered why she's so hesitant to speak to Marianne herself. But Marianne had increasingly fallen into sensibility from their father's death until Willoughby leaving, she might feel faintly excluded or pushed back. She might feel that she does not know how to address her because she's seen the result of trying to talk logically and impassionately to her and Willoughby.