I first searched for a P* Rybak, and narrowed it down further by inserting 1928 +/- 5 years for birthdate. Only Pessa came back with a birthdate in the range that would have been appropriate for her school and to have signed the album.
I was able to find Pessa's family through matching addresses. Her family included a father, Chaim (b. 1895); a mother, Sura (b. 1896); and a number of youth that could be either siblings or cousins, including Brucha (b. 1919); Szejwa (b. 1922); Nuta (b. 1924); Rywka (b. 1926); and Mojsze (b. 1933).
There are two members of the family for whom no deportation information is listed. Brucha has only a date when she changed addresses, November 25, 1941 (which could also possibly be the change of date of address for the rest of the family.) The other family member is Nuta, who died of (currently) unknown causes on March 18, 1942.
The rest of the family was deported on two different dates. The children were all deported on March 20, 1942, and the parents were both deported on March 22, 1942. These were both during the month of daily deportations to Chelmno.