]2) In chapter 39, Lydia says something that I would never expect her to say: "Oh! Mary ... I wish you had gone with us, for we had such fun!" Then almost immediately after, the narrator says Lydia "never attended to Mary at all" -- which is what I had always thought. So where did that "wish you had gone with us" come from? I don't think Lydia would notice whether Mary was there or not, and Mary would certainly not partake of any of Lydia's "fun".

Sorry to say I can only comment on your #2, which does seem strange coming from Lydia. I think it's only an off-hand comment she makes to Mary, in order to give her more of a chance to talk.