I personally use a vaporizer at night. Apparently the only reason docs suggest the cool mist one is to avoid accidental burns. But if we're talking about a baby who will be in the crib, then the burn factor is highly unlikely. Also, the cool mist can harbor bacteria, and can aggravate some conditions. You can do a search on Google for "vaporizer vs. cool mist humidifier" and find more info.
I also use something called olbas oil--you can get it at a lot of health shops. Just put it on the back of the pajamas, so that it won't get into baby's eyes, or on baby's hands (then transferred to the eyes). It helps. And whenever someone in the family takes a shower, take the baby into the bathroom so that the steam can help to clear the nasal passages. Good luck.