Found 3 births to John Balfour and Edith Sarah in SA
Edith Ellen 1878-08-07
Myra Lucy 1886-10-19
Also 2 births in New Zealand
Henry Basil 1875
Charles James 1876
There is also a marriage in SA for Mary Elizabeth Anderson (father listed as John Balfour Anderson) to Roland Young 1897-03-04.
This link for WA BDM and you will find Isabel's marriage to Eric Rumble in 1915.http://www.bdm.dotag.wa.gov.au/_apps/pioneersindex/default.a...
It would seem that Edith and Myra never married?? Search for the name Anderson and you will see their burials and also one for a John George Balfour Anderson.http://www.mcb.wa.gov.au/NameSearch/search.php
Searching the Trove website will also give you a bit more info.