Just jumping in here to try and answer your question about widowed women being listed under their maiden names.
It was and still is in Scotland at least quite legal and customary more especially in byegone days to continue to use your maiden name after marriage, widowhood or divorce. If you are searching for a marriage, remarriage or death on the Index at Scotlands people it will be listed under all previous names.
I hope I have explained this properly,
Dorrie