Thank you for your answer. I had forgotten Mr Bennet was Sir Riley's friend. It makes sense most of the family would stay in Sir Riley's home rather than with the Fitzwilliams. My main doubt was whether Mr Bennet was willing to impose his wife on the Matlocks with only Jane and Lizzy to check on her behaviour (as Mr Gardiner will not be up to the task in his state). As you didn't mention her coming back to Longbourn with the Phillips, Mr Bennet, Mary, Lydia and the older Gardiner boy, I assumed she would stay with the Matlocks instead of going back to Longbourn with Mr Bennet, Mary and Lydia. And I say yes to Kitty staying with Sir Riley's family to advance her friendship with Julia and her brother, and as far from Lydia as possible.
