she’s the right age for teething, which is when puppies’ gums are sore and eating can be painful. this is also the age both of my puppies went through a stage where they didn’t want to eat anything, so i would use that as an opportunity for training. i would put the bowl down and leave it for 15 minutes, and if she doesn’t touch the bowl, pick it back up. i would use her kibble as training treats so she’s working for it – you should be working on basic obedience right now, anyway, so it’s an ideal opportunity for that.
once she has all her adult teeth in, she should go back to eating normally.
i would keep things she shouldn’t eat out of her reach.
i don’t know but i DO know i’d be getting him to the vet.
and please, don’t let him back outside. you live in an area with a number of animals that can cause your cat harm or kill him. if you care for him, you’ll keep him inside, where he’s safe.