If your stories are of the supernatural, why not choose songs on the same theme? Plenty of the old ballads concern ghosts and magic or, if you must have something with a chorus, there are good versions of 'The Unquiet Grave' with singable refrains.

On the other hand, chorus songs are a high-risk strategy with an audience unused to the concept of singing along. Keep your chorus VERY simple, would me my advice if you want to go down that path. 'Dido Bendigo' has a wordy chorus full of obscure names. Personally I wouldn't go with song-sheets unless the evening were advertised as some kind of singalong. Some people might regard having a songsheet pressed into their hands as a bit too much like school.

My experience is that non-folk audiences appreciate songs that challenge their preconceptions (which tend to consist of jolly choruses sung by men in chunky jumpers). A stark rendition of a beautifual melody, with a good and perhaps mysterious story might really grab them, never mind whether it's already familiar.