Yes, I think we're supposed to take from it that she is just pretending to be Lizzie's friend (and by extension, also pretending to be Jane's). But in the book, there's a definite financial motive - it wouldn't be good for her if her brother married Little Miss Penniless - whereas I don't think that works so much in the LBD, so she would have to be motivated by personal animosity towards Jane and/or Lizzie.

And it's hard to imagine anyone being motivated by personal animosity toward Jane.

But maybe Caroline was more angry about Lizzie's videos than she let on...?

Someone requested Caroline Lee fic for Yuletide, and I hope someone takes that up and digs into her motives more.