Tank is 99.9%! Her skin's cleared up and her fur is eagerly growing back. She's now eating and drinking on her own, which means I no long have to feed her by hand and aside from her trying to clean her self, cone on her head and all, she's back to her good old self.
I'm glad that I went with my gut feeling and didn't put her through being sedated under local anesthetics to get a skin biopsy etc. etc. done. I'm happy that my vet wasn't overbearingly pushy about it and agreed to give her a second course antibiotics before proceeding into more serious treatments.
You can kind of see in the photos where Tank had lost her fur on her head and back. It was a lot more noticeable a couple weeks back, as her skin is actually white! Slowly her skin darkens with little tiny black fur follicles and then becomes like peach fuzz. A couple weeks later, her grey/white undercoat grows in and her black "outer-coat" grows over.