Yes, that is what seems to have happened. I accept it's a strech to get any other interpretation out of what we see. I just like the idea of Kitty marrying Edward and being part of the family. I at least tell think that might have been what happened in the original timeline.
I do think there could be a good audio about Kitty's life before she came to Collinwood, especially with Petofi's involvement with her husband's suicide.
This is just a crazy theory. I've read a fan theory before that Josette could've had a twin sister that died at birth or infancy, and that Rachel was the reincarnation of the twin - and possibly Maggie was the reincarnation of Rachel.
After KLS played Josette's mother in the audio The Crimson Pearl, it occured to me that Rachel and/or Maggie could be the reincarnation of Josette's mother. All of this is based on their appearance which in "real life" has nothing to do with reincarnation, but I'm just using DS logic. I don't really think this is the case, but it's still fun to speculate and make up wild theories, DS is very good at inspiring the imagination.