Gender: girl
School:
School #4A
Searching 'Pesia' and 'Weltfried' under fuzzy parameters, I came up with Pesa Laja Weltfrajd, whose birthdate put her in the right age range to have signed the album. Pesa and Pesia are not that different, and Weltfried and Weltfrajd sound similar in Polish pronunciations.
The family members I've found all had the same addrss as Pesa. This includes a father (Alter, b. 1902), mother (Raca, b. 1902), and siblings Juev(?) (b. 1925), Dyna (b. 1927), and Rachmil (b. 1934).
They were all deported on the same date (except Juev(?), who has a death date (from unknown causes) listed as May 10, 1942). That date is September 11, 1942, on which date there was a deportation to Chelmno.