Hi Kay,
still no luck with your Orr family i'm afraid. so, assuming they were in the mid to south of Scotland somewhere - i can't find them any further north - there are four households where i have found a Peter and an Agnes living in the same house. - they don't look very promising though, as none have children with names of Christina and Elizabeth, and some aren't even old enough to have children.
i am not too sure where to look next. i have checked the name index for the whole of the british isles against all four names with and without dates, and i can find no matches where the four names are listed in any one place together. - any ideas? - i even checked surname variations such as orre, corr, carr.
i have found a few details on the igi though which you may or may not have already which would appear to be this family. - hopefully this may help you a bit:
CHRISTINA RITCHIE ORR
Female
Birth: 19 JUL 1866 Edinburgh Parish, Edinburgh, Midlothian, Scotland
Father: PETER ORR
Mother: AGNES CHIEN RATTRAY
ELIZABETH LAING ORR
Female
Birth: 02 MAR 1874 Edinburgh, Midlothian, Scotland
Father: PETER ORR
Mother: AGNES CHIENE RATTRAY
PETER ORR
Male
Spouse: AGNES CHIENE RATTRAY
Marriage: 23 FEB 1866 Dirleton, East Lothian, Scotland
AGNES CHIENE RATTRAY
Female
Christening: 02 JUL 1843 North Berwick, East Lothian, Scotland
Father: CHARLES RATTRAY
Mother: CHRISTIAN RITCHIE
PETER ORR
Male
Christening: 03 JAN 1847 Kirkliston, West Lothian, Scotland
Father: GEORGE ORR
Mother: ELIZABETH LAING
sorry i can't help more, but if you think of anything else, let me know and i will be happy to try and help.
kind regards, Lorna.