ARTIE UPDATE:
We haven't rescued her yet, but we made face-to-face contact, even got her close enough for a scritch and a treat from Peg's fingers. She has food and water we have confirmed she has access to. Not remotely resolved yet, the hole we found in the attic is too small and she's SUPER skittish about leaping down (understandably, she's gotta do it from a rafter), but...
WE KNOW SHE IS ALIVE, FED, AND HYDRATED NOW. Tools and Attempt #2 tomorrow morning. May seek carpentry advice soon.