Some breeders also like to hang on to the best until last..haha.
She may very well calm down nicely. She may just need more time then the young-ins. Until she starts eating, I would do nothing more but the most basic maintenance. I would leave the other little one that isn't eating be, as well. You now know they will do nicely.
Perhaps you can try "leaving" a dead rat with the Matrix to see if she will take it once she has privacy.
Do they have privacy on the sides and back of the tub? Layer more newspaper on top of them, and make sure they are enclosed sides, back and top. They will eat once they feel safe and comfy.
If you want the Matrix for breeding, she should calm down enough to be handled for sure, she may not get to be puppy dog hang out with you for fun tame, but handle-able? Absolutely! And who knows, she may surprise you. But first things first, get them eating![]()