Sneezing isn't the same as coughing, it sounds like Pfew-Pfew-Pfew, and can happen now and then, quite normal. Irritation, dust, etc. can make rabbits sneeze. Same as with humans.
It only is something of concern when it it happens often and regularily, and when there's discharge. One of my does sneezes rather often, about every day for years now, about 5 times in a row, but she's healthy and there are no signs that something serious is off. It's not a good sign and something to keep a close look at though. If you ever get to a rabbitry with sneezing all over the place it's best to turn around.
Coughing, like when something gets logded or in the wrong tube sounds horribly, didn't hear that often. But when I jumped and ran to see what is going on.
