She appears to be buried at Calvary cemetery according to that, which would suggest the family are Catholic.
Possibly the girls were at St. Paul's R.C. Orphan Asylum which was in Chartiers?
Here is where you'd need to ask for records for St Pauls:
http://diopitt.org/office-archives-and-record-center/information-genealogistsOrphanage Records
We have orphanage records from St. Paul's Orphanage, St. Joseph's Orphanage, and Holy Family Institute. Information in these records consists of the child's name, date of admission, and date of departure. Other information that may be included are father's and mother's first and last names; correspondence; grades; medical records; whether Baptism, First Communion, or Confirmation were administered and when and where; and reason for placement.
By search-scamming on the free indexes at Ancestry, I found that there was a John Shustic, parents John and Annie, b. about 1864, d. 1906
I also tried to look up any probate and the nearest thing I could find was this.
"Jusefa Szotek", "M" (minor?), "Frank Szotek, Gdn" (Guardian?)
https://familysearch.org/pal:/MM9.3.1/TH-1971-28782-705-55?cc=1999196&wc=9PMF-T3L:268499101,270443101Could this be "Josephine"?
vol 28 / page 240 / book 6
Which refers to here, and another cross reference
https://familysearch.org/pal:/MM9.3.1/TH-1961-28782-28102-88?cc=1999196&wc=9PMN-ZNP:268499101,280384701docket: OC, vol 158, page 513, no 201, Nov 1905 - guardian appointed?
Unfortunately
Pittsburgh directories (
http://digital.library.pitt.edu/p/pitttextdir/ )show, in addition to the 1906 at 2812 Edwards
1909: Szostek Frank mill wkr 1809 Fox
1912: Shustik Frank lab 1809 Fox
1913: Schrostic Frank lab 1809 Fox
1914: Chostik Frank lab 1809 Fox
1915: Kostek Frank lab 1809 Fox
1916: Szotek Frank, lab, h 1809 Fox
I think these may all the same person, with varying levels of errors added between him giving his name and it getting printed (there may be more entries, I found these by searching on the address and it's OCR not manual transcription).
Perhaps if we could find this man in 1910 that might clear something up. Anybody know how to search the US census by address?