New feathers coming in is great news! Is she eating good? Feed her some cat food if she'll eat, the protein would do her some good. You could go the weaker Wazine route today if you have a working vehicle. Otherwise a little DE wouldn't hurt.
I would repeat whatever seemed to be working last time around as far as antibiotics, food, etc.
I'm working with a hen who has peritonitis. I've got her on some expired Baytril. It seems like she starts making improvements when I put the Duramycin in the water. I don't know if it's just because the Baytril is older or the water soluable works better than I thought.
Do you have a little gatorade for her, you can put a splash in some water it'll encourage her to drink.
btw: When was the last time you treated her for the mites/lice and with what?