Congratulations on your new chinchilla.
Hopefully, you kept Kiwi in quarantine when you got him. If not, I'd put Kiwi and Bailey in separate rooms right now. Hopefully, Kiwi hasn't already been exposed to whatever is causing Bailey to be sick. I'd also watch Kiwi closely for any signs of illness if he was anywhere near Bailey.
I talked to several breeders, and have found that taking a chinchilla to a vet is deadly because the chin becomes overly stressed.
That seems very odd to me. Yes, a chinchilla can potentially become stressed from a trip to the vet. However, it is hardly going to be deadly to them. I have taken many of my chinchillas to the vet. Sometimes it was because they were sick. However, when I moved to Jacksonville and was looking for a good chinchilla vet, I took healthy chinchillas to different vets for check-ups to try out the vets and find one I liked. None of these chinchillas ever got stresed out to the point where they died. In fact, once they were back home they didn't seem to have minded the trip at all. Many times they were relaxed enough to sleep in their carriers on the car ride home.
Another reason it seems odd to me, is that if a chinchilla became so stressed from a trip to the vet that it would kill them, then a trip anywhere would be too stressful and most likely kill them. That means just getting a new chinchilla and bringing it to your home would be stressful enough to have the chinchilla die. Obviously, that hasn't happened.
Any good breeder will tell you that if your chinchilla is sneezing, it needs to go to the vet right away. Once a chinchilla shows signs of respiratory problems, if they are not given vet care and put on antibiotics, the chances of them recovering are very slim. From my experience with respiratory illnesses in chinchillas, they take hold quickly and the chinchilla needs to go on antibiotics immediately. Also, since chinchillas are prey animals and hide illnesses well, you may not realize how sick they really are. Therefore, it is a very serious problem.