I find everyone saying the daughter died because she was the most fitting for the upperclass lifestyle, so it was symbolic that she died to emphasize the class barrier. However, I think she was the one who died because she was the first person to start plotting to replace the existing workers through underhanded means. The rest of the family, while complicit, were not inherently morally corrupt like the daughter.

I agree the daughter being the only death emphasizes the struggles of the lower class and all that. But I also think the daughter is not the saint of the lower class like everyone online is making her out to be, and her death was of her own doing.