A Banshee is not the same as a Ghost-- it has its own flavor and setting.
The banshee is a female ("ban") fairy ("shee" or "sidhe") who cries when one of the old families of Celtic lineage is about to pass. Each banshee has an adopted family and will follow and watch over the descendants wherever they go (even across oceans). In fact, according to tradition, the banshee can only cry for five major Irish families: the O'Neills, the O'Briens, the O'Connors, the O'Gradys, and the Kavanaghs.
When she is sad, she appears like an apparition of silvery hair wearing a grey cloak and bearing red eyes from crying. At other times, she is a young girl with red hair dressed in green (Irish fashion). Alternatively, some say the banshee has three different appearances each representing Celtic goddesses of war and death, namely Badhbh, Macha, and Mor-Rioghain.
Not all ghosts wail like a banshee. Nor does every ghosts specifically have to do any of the things mentioned above.
Why not suggest we only have a general "monster" template while we're at it?