The Christine photos are beautiful! I don't recognize them, I don't think they were published anywhere or any other photo where she's wearing that white sweater. Based on her hair I think they were from before Rumours was released, so '75 or '76.
There are a lot of Rumours outtakes floating around, many have been published in some form or showed up at auctions. I have a folder with currently 57 different photos from that shoot:
http://i.imgur.com/DsyAmjH.jpg but I've never seen an auction for the actual negatives.