Came across tweets that we've missed, which I've tweeted about
here, from a woman who says she is stand-in for two different actresses. Looks to us like she's stand-in for Lena Headey and Jennifer Ehle, the only two adult principal women that I can recall in the script.
She describes one scene as her walking out of the castle's "cellar" with a handmaiden carrying her train (Catelyn going about making sure all's ready for the feast, or Cersei leaving the Stark crypt? she demured in the books, but perhaps they're having Robert make her do it). She also notes that Sean Bean's stand-in is giving her a lift. However, she's not required before 10 AM ... so I think it's a good bet that Ehle and/or Headey won't be around before that.
Finally, she says she's need for Monday and Tuesday. So, looks like the principals -- or at least the leading ladies -- are not going to be around after that.