SUCCESS!!
Tonight was feeding night. I placed Clementine inside her toothpaste box because it's dark and cramped to help her feel secure. Thawed a pinkie in hot water, washed it with Ivory dish soap (had to make a trip to the store for that brand specifically, haha), and ever so gently wiggled it in the front end of her hide. I've watched her in the past be very interested in movement and I was hoping to replicate the movement that a live pinkie would make. It's really hard not to just harass her with it. She was acting very interested in it but eventually retreated into the back end of the box. I rinsed (and reheated) the pinkie, dried it off this time, and also brained it. Then repeated the process of really gently jiggling it and let her come to it instead of putting it right in her face. Again, she was very interested and stuck her mouth right in front of the brained area and then after a few arm-tiring minutes of making it crawl around, she opened her mouth and ate it. Such a relief! I hope next feed requires less work though!
Picture of little stinker finally working it down in her box: