She's absolutely fabulous. She spent the day in my office again today (walked in voluntarily) but I'm thinking that's not needed. They are hanging out in the kitchen for treats, and this evening she actually walked over to Sophie and gave her a face to face rub and purr. Sophie was quite startled, but didn't panic.
Ellie's history is a cipher; she was pulled from a shelter in another county just two days before I adopted her. I have to think that this was a serious illness/death/last ditch desperation measure to put this cat in a shelter. She's a freaking dream. Best birthday present I got myself ever.