score:6
In this photo, the little girl at left is Lily Yu, daughter of Xunling Yu, court photographer and brother of Der Ling. This has been confirmed by family of Mme Dan Rongling, sister of Der Ling and Xunling.
One more thing I can add about Lily: she was born in 1893. As to what happened to her later, I could never find this out. The family seem to have disappeared in the melée of Japanese invasion, Mao's victory and the cultural revolution. Her father, Xunling, died in 1944. I write about the subsequent life of Der Ling's sister, Mme Dan, who lived into her nineties in Beijing. She was attacked and killed by Red Guards in the street outside her apartment near the Forbidden City during the cultural revolution.
My 2008 biography of Der Ling contains everything verifiable I could find out about the family.