for the first cat, it is possible he got snagged with the claw of the other cat while playing and it got infected and finally burst open (abcess) or he could have gotten bit by a spider. for the second cat, sometimes cats go through stages, i had a yr old female that went for at least a month throwing up every single night, just once a night, and other than that she appeared perfectly fine. she got over it and is still perfectly fine. she happens to be a, what i call scaredy cat, almost scared of her own shadow, and i think she goes through high stress periods and the high stress makes her throw up. sometimes cats will meow with now sound, healthy or sick, but maybe her throat is raw from throwing up. if she doesnt show improvement, and there is nothing to cause her stress, consider taking her to the vet. i hope both your kids recover quickly and completely.
i would like to add that unless the vet gave you something, i have successfully treated (with vets approval) abscess on my cats tail base using peroxide and iodine. being above the eye would make this hard to treat, so try putting neosporin on it.