Aokashi, if life food isn't stimulating then you probably will have to force feed if you want the poor guy to have a chance. What I did when I once tried to force feed a betta is I took an eyedropper and dipped the the tip into thawed baby brine shrimp (daphnia would work too). I very gently put just the very tip of the eyedropper into his mouth. If he is gasping or breathing heavily, wait until he opens his mouth. It helps. I can't say if this method works or not but it's how I tried it. It's like the fish equivalent of feeding soup to a sick person.
Peggy did well at the vet because she LOOOOOOOOOVES the attention. Haha, the vet was actually trying to annoy her so she'd stop purring because the vet couldn't hear her heartbeat. Vet put her on prednisone for a week so we can rule out any possible allergies. If that doesn't help her stop with the licking/chewing, then it's probably behavioral and then I imagine things get tricky. :/ If it's an allergy, then I'm 99% sure it's a food allergy since this is an indoor only kitty.
Peggy does have Siamese in her somewhere (wouldn't know from her fat stubby appearance though). She is a talker too. Jen, I think my cat and your Old Man are related. Haha, except Peggy is a grump when it comes to other cats.
Crowntail, have you been to a vet? From what I learned today, it could be an allergy and if it is, they can treat it.