Keep close watch over them. It sounds like upper respiratory infection. Make sure they are eating well as kitties go by their noses (smell) for their food and if they're stopped up they can't smell and don't want to eat. Soft catfood is smelly so they will hopefully be more inclined to eat it. It also helps to turn on a hot shower and put them in the bathroom with the door closed for awhile. And also watch their eyes for any runny ness. If there is, get with the vet to get an antibiotic ointment. Some vets put kitties with URI's on a liquid antibiotic to prevent secondary bacterial infections. I don't mean to sound scary with all of this but from fostering for animal control I have seen lots and lots of URI's. Keep us posted on their progress!