The voices heard on the soundtrack belong to Sue Tilbrook (who also appeared in Scayrecrow (2008) as Eleanor Tawney) and her eldest son Joshua Taylor.
The 'identity' of the Skull is never explicitly named, although if the viewer listens very carefully during the montage sequence a number of clues are given to whose skull it might once have been... and how it came to haunt the house.
The imposing male figure in the oil painting (meant to be Azariah Penraddon, the Magistrate that built the manor) hung above the skull, is actually a still taken from unused footage shot for Scayrecrow (2008). The actor is Barnaby Kingsford and the character was Governor Thorndike, the official that paid for Rookwood's capture / execution.
The terrifying scream heard at the end of the film (and at the climax of the trailer) is not a computer generated effect. The scream was done live in one take by composer Mick Grierson. (The distortion heard was a consequence of the performance).