Hello Maria! I read your long answer to that question about who is and who isn't faithful to the Starks and I wonder cos I haven't read all the books yet: how do people from the North react to that fake Arya being brutalised? Do they try to save her?
The ones that are not close to Winterfell can’t do anything just yet, but join Stannis –who is trying to retake Winterfell– hoping to save her. House Mormont, the Mountain Clans and other houses have joined him, and I’m sure the underlying hope is to get to Arya (”Ned’s little girl”, as she’s often referred to), and save her from the monster they all know Ramsay is. Jon, who as Lord Commander can’t directly help (because the Night’s Watch takes no part) does try to dave who he thinks it’s Arya by sending Mance and a group of spearwives to bring her to the Wall with him.
The people who are close have to play along with Bolton; because they are “allies”, or at least are pretending to be. They are powerless, because saying a word to spare Arya will uncover their own alliance. But they are not happy about it:
“Dressing her in grey and white serves no good if the girl is left to sob. The Freys may not care, but the northmen … they fear the Dreadfort, but they love the Starks.”
“Not you,” said Theon. “Not me,” the Lady of Barrowton confessed, “but the rest, yes. Old Whoresbane is only here because the Freys hold the Greatjon captive. And do you imagine the Hornwood men have forgotten the Bastard’s last marriage, and how his lady wife was left to starve, chewing her own fingers? What do you think passes through their heads when they hear the new bride weeping? Valiant Ned’s precious little girl. […] Lady Arya’s sobs do us more harm than all of Lord Stannis’s swords and spears. If the Bastard means to remain Lord of Winterfell, he had best teach his wife to laugh.” (Theon, ADwD)
People’s patience with Ramsay’s brutality is running thin, and, as Barbrey says, it could have ended in a rebelion against the Boltons within the walls of Winterfell.
Also, I think quite a few of them do know it’s not Arya: Jeyne doesn’t look like her, and she’s older; so people who were familiar with Arya will see though the lie (though I hope they are still disgusted at the idea of a poor child being tortured, even if she’s not a Stark).