One thing I look for is mucus on the side of the tubs. They will rub their mouths on the side of the tub and leave mucus marks. Other than the wheezing, look for a lot of bubbles or mucus coming out of their mouth. It will look sort of like they are slobbering. Sometimes it's a thick mucus, sometimes is a really runny mucus. To me the mouth looks fine in those pics. They also do a lot of open mouth breathing when it's really bad.