Oh, you are gonna be so happy! I was writing up a little blurb for you with ideas and suggstions of how to approach your interesting problem systematically --- and decided to test my ideas before putting them here.
First let me share them with you 'cuz it worked, and you can finish up if you like my approach.
I would methodically check for each sister in, first, available English census records. 1891, 1901. See who is where and if you can determine which one had the nickname Sally. I do know that gals named Sarah are sometimes called Sally, so that might be a clue.
Then I would methodically check for each sister in USA census records. I'd also check Canada, just in case.
Ok I started with Charlotte and saw that in 1901 she was a servant in another house. Her sisters were still at home. I started thinking that maybe Charlotte, who had already left home at a fairly young age, went off to N. America.
SO..... I had a little peek around and lo and behold I found her marrying in Ontario Canada on 26 July 1924 to Paul Osatchuk in York County. (I bet your "Strabanic" is this guy - Ostachuk)
Ok the marriage record lists her as Charlotte Sarah Maxted, d/o Henry Maxted and Charlotte Cheney. She is 38 born England. Her groom is 34, born Russia with parents M Osatchuk
and Pelagia Waloshen.
And guess what - the witness is Mary Patalko of New Toronto.. wanna place a bet that this is Charlotte's sister Mary Maxted and Patelko is your surname Petacal? Do you think two sisters left? Could they both have come to Canada and married? If yes, wonder which one went on to Pennsylvania...
It looks like the second witness is Toney [sic] Harroway also of New Toronto. it looks like they married at Long Branch in Church of England ceremony. Groom is Greek Catholic, she is Anglican
I'm pretty excited about this! If you want to keep searching for census see
http://allcensusrecords.com/ for help. And Ontario Vital Stats Project is transcribing these marriages, (also births and deaths) so you might want to search further. For help see
http://olivetreegenealogy.com/can/ont/ and choose Vital Stats