From the NYT article:
“You want to do everything they know the piece to be, and go much deeper,” said Mr. Grandage, the show’s director. “It is incumbent upon us to come up with surprises.”
That means new elements starting right at the beginning: Whereas the movie opens on a frozen lake, with a group of singing ice harvesters, the musical will start in a verdant landscape, with a group of scruffy (covered in greenery), sexy (greenery only goes so far), tailed creatures, called hidden folk, drawn from Scandinavian folklore and chanting in Norwegian.
Huldufólk (Icelandic and Faroese hidden people from huldu- “pertaining to secrecy” and fólk “people”, “folk”) are elves in Icelandic and Faroese folklore. Building projects in Iceland are sometimes altered to prevent damaging the rocks where they are believed to live. According to these Icelandic folk beliefs, one should never throw stones because of the possibility of hitting the huldufólk.
They are also a part of folklore in the Faroe Islands. In Faroese folk tales, Huldufólk are said to be “large in build, their clothes are all grey, and their hair black. Their dwellings are in mounds, and they are also called Elves.” They also dislike crosses, churches and electricity.
Broadway kristoff is an elf prince