In a search for B* Kestenbaum under exact parameters, 3 results came up. 2 were in the age range appropriate for the school, but only one was a female, and that was Bluma Kestenbaum.
The family members I found for Bluma all lived at the same addresses as she did. These family members include a father, Izrael (b. 1904); a mother, Mindla (b. 1904); a twin brother, Efraim (b. 1931, same date as Bluma); a younger brother, Ber (b. 1933), and a younger sister Chawa (b. 1938). Chawa is the only one that did not live at the Sulzfeldstrasse address.
All the children had identical deportation dates: September 12, 1942, on which there was a deportation to Chelmno. Mindla had no deportation or other information in her record regarding her fate, and Izrael died of (currently) unknown causes on April 3, 1944.