Is Lu's daughter her own?

No, according to the query "teachers always ask parents", we know that:

1. Lu Xingzhi's daughter is not her own. Ningning was the daughter of Dumei, the victim of that year. She witnessed her mother being brutally killed.

2. Lu is a character in the novel "There is always a teacher asking his parents", in which Lu Wei is the daughter of Lu's brother. The play tells the emotional story of Qi Yan and Lu.