Living dangerously for an Austen nerd

Deadline just posted a casting update on the Jane Austen project I'm most curious about: the upcoming ITV/PBS Masterpiece adaptation of Austen’s unfinished final novel Sanditon. I'm concerned about the description of the heroine (nothing in Austen's fragment implies that she was meant to be "impulsive, spirited and unconventional"), but the story is so wide-open that they can take it almost anywhere, and I'm excited to see where that leads.