A bit of an update on FG, although I've barely touched her for a couple of days. I did manage a little bit tonight though.
Giving the cat his antibiotics has turned out to be a lot less stressful than I thought it might. I've found grinding up the pills and mixing it with a teaspoon of cat food, and giving it to him just before he has his usual food means he's hungry enough to eat it without too much fuss. So far so good anyway! It's definitely having an effect - his breath has stopped being foul.