D.
Your child is alot younger than mine but my 4 yo daughter has alot of problems with croup. We have been to the ER twice in the middle of the night because of uncontrollable coughing and trouble breathing. Here's what we do now so that we don't have to go to the ER. We can treat it ourselves at home. Actually steroids are the best thing to give for croup so your child doesn't have trouble breathing. And to my knowledge cough medicine isn't going to help at all.
Cold will help calm down the coughing. We will put my daughter's face up close to the open freezer and have her breath in. If it's the winter we'll take her outside and let her breath in the air and we have even have taken her for a car ride with the windows down. Also if we give her crushed ice to suck on that has helped alot. Your child is young so maybe substitute one of those freezer pops or something like that.
Another thing our pediatrician has prescribed that helps alot is pulmicort. It has to be administered through a nebulizer machine but I've been told it's the next best thing to epinephrine which is what my dd gets when she goes to the ER. This option isn't the cheapest one out there but if you start to have alot of problems with this, you'll want to have it on hand.
And the last thing we've done is give my dd zyrtec during the bad allergy season. That has practically stopped the croup for her. In her case the cause of it was apparently allergies and getting those under control has helped stop the croup. That's not something you can know right now but if it starts to be a problem especially during spring and fall then that is a possibility.
Oh and the cold mist humidifier of course along with Vicks vaporub help too.