When you go back through the pension file, the John W. Dungey affidavit agrees that Lydia's maiden name was something like Lukens or Lookin, and he also knew Jacob and Matthew in Illinois. Haven't been able to find any information on the cemetery beyond the stone inscriptions.
When you look at the 1865 census page, you'll see that Bartley's sisters Jane (Safford) and Elizabeth (Provin) are living right next door. I would bet that one or both of them were caring for the children.
I keep going back to Lydia (one of my daughter's is named Lydia) but have never had that big break through on just who she was yet.