Ok, sorry for the delay I tried to send my answer but it would not go through therefor I had to retype.
The two most troublesome things right now are the fact that she has been able to run a fever for over a week, the sudden paleness in the gums and ears should be treated as an emergency as this can be a sign of internal bleeding, anemia or shock.
This baby really needs to have blood work done including a feline leukemia/feline aids test. I am not sure how lymphoma can even be mentioned with out additional basic diagnostic tools, as you have not provided any symptoms that would lead me in that direction (of course I do not have a full medical history)
If you live in CA,AZ,or TX then coccidoidomycosis (valley fever must be considered)
Pemphigus Foliaceus which is an auto immune problem which causes the body to attack one of the layers of skin and will cause hair loss and itchy oozing skin.
Hyperthyroidism can cause all the problems you are seeing including the hoarseness and gagging, this is a common problem in cats, however it normally develops after the age of 8
1 negative skin scrapping may not rule out the presence of feline scabies as these can be hard to find steroids may actually increase this problem
There are several different fungal infections that can also cause this problem
Here is a web site that details skin disorders in cats
I also need to say that just because a cat lives in doors and you do not see fleas does not by any means indicate they are not there, if she has developed an allergy to fleas then not only will the bite effect her but also the saliva that they leave behind
If you are using plastic food or water bowel this can be a source of allergen to cats.
Severe infestation of hook worms can cause anemia(pale gums) itchy oozy skin, gagging as they move into the esophagus, and hoarseness due to irritation
Since this started so recently please try to think if there has been any changes in the house hold carpet powders, sprays, air fresheners and febreeze, laundry soaps, shampoos, can all trigger allergic reactions.
I would suggest having Skin scrapping, tape tests fungal cultures and cultures of the discharge that is coming form the skin need to be done, I would suggest having these tests sent to a lab and not done in house.
Blood work needs to be done to check for infection and the cause of the pale gums and fever. Blood work can also check for hormonal imbalances, a fecal exam will rule out any intestinal worms or parasites.
Skin issues can be so frustrating and since you are not seeing any change after 2 vet visits I would suggest getting your vet to refer you to a veterinary dermatologist who specializes in skin related problems
Again I will say that the pale gums and ears have me very concerned, if having her seen tonight at the animal emergency is an option that would be best
I hope this has given you some additional information to discuss with your vet, please reply back if you have additional questions or concerns