What an interesting question! Let's see...

I can see Snow White, Cinderella, Aurora and kinda Anna liking a castle that had a romantic feel to it. I can also see them preferring a castle that has a happy, open air about it.
As for Ariel, I think as long as it's not under water but still close to it she be happy anywhere.
For Belle, I'm not really sure. I guess for her as long as it's not dark and a prison she would be happy in any castle.
I think for Jasmine she would like an open no walls around it type of castle. One where she could come and go as she pleased. And maybe if it had a Middle East feel, the better??
Pocahontas would like an open castle would she wouldn't have to spend to much time indoors.
Then for Mulan, I think she would like a castle that had a Chinese, or at least an Asian, feel to it.
I'm not sure about Tiana. I think as long as she got to cook she would be happy in just about any castle.
For Rapunzel, something similar to Belle and Jasmine. A place where she can paint and be free to come and go as she liked.
Not to sure about Merida, but maybe somewhere where she can ride horses and explore??
Then for Elsa....Maybe something on the cold side, a castle that while not made of ice is in a coldish climate.
And I know she's not out yet and wouldn't be for a few months, but for Moana, I can see being like Pocahontas (an open castle where she can be outside most of the time) and Ariel (close to the sea/ocean).

I don't know much about these castles...or any castle for that matter, but if there's a castle that fits all or at least most of the above then that's the castle I think the DPs would choose to stay.