The person who created Barasuishou wansn't Rozen, it was Rozen's apprentice. He tried to create an eighth doll to win the Alice Game for him. No one knows what happened to Rozen or where he is.
Barasuishou crumbled away because she was beaten by Shinku, and because she wasn't a real Rozen Maiden doll, so when she was defeated, she was completely destroyed.
As for Laplace's Demon, (that rabbit thing) the dolls knew his name from before, and when they figured out that he was the Apprentice's apprentice (/secretary or something) he didn't need to pretend anymore. They knew him from before.
As far as Souseiseki and Hinaichigo go, I have no idea. I'd like to think the did come back, but Hinaichigo was sort of doomed from the moment she was beaten by Shinku (in like the first episode of the first season) because she had to live of the energy Shinku passed to her from Jun. As for Souseiseki; I don't know, she was beaten fair and square by Suigintou (if I remember correctly) and had her Roza Mystica taken, so I guess she
actually lost the Alice Game. The other dolls were "killed" by a fake doll, so maybe that didn't count. So if from what I understand about the Alice Game is correct; they were beaten by actual Rozen Maiden dolls, so No they didn't come back.

Kind of a downer.
Amazing series though, It was what got me into anime.
EDIT: according to the wikipage, Souseiseki and Hinaichigo's Roza Mystacae's are in the possesion of the Rabbit, and they're both in a "deep sleep" and their fates are still unkown.