Thanks for very interesting post. I don't think FW is jealous of Benwick, because FW considers Benwick attaching himself to Louisa after Fanny with some surprise. So Benwick ceases to be a threat at the same moment as the possibility of him being a threat might enter FW’s mind. But certainly Benwick’s appreciation of Anne rouses FW’s attention to Anne’s superiority of mind, just like Mr. Elliot's appreciation of Anne rouses FW’s attention to Anne’s looks.