Are the walls finished? Concrete or framed and sheetrocked? If it's only concrete, a waterproofing paint like Dry-Lok, (not sure of the spelling) will make a big difference on the walls. If that wasn't done, and they are already sheetrocked, it can be a problem later on. Also what Drew said about the humidifier draining is very important. Before I had mine set up like that, sometimes I would forget for a few days to empty it. I have mine on a shelf next to where my washing machine drains in the wall. Just used a piece or garden hose from the pan to the pipe in the wall. With it being up higher, since humidity settles, you might want to use the fan idea or put the setting a little higher. To get rid of the smell, if you have one, you will have to keep the basement dryer than normal for a while. Though I never heard of the charcoal, I bet it would work very good.
Best Of Luck!
Steve
PS BTW- A dehumidifier running for a significannt amount of time will raise the temperature in the room. But remember that dehumidifiers remove more water, the higher the temperature is. That is a fact, some even come with a chart that show maximum water removal at different temperatures per humidity level. In fact if the room is too cool, even with the dehumidifier running constantly, it wont remove any water from the air.