Is Mr Frost the Man Jack?

Researching the murder of Bod's family, Scarlett learns that the historian lives in the house that Bod's family once lived in. Bod visits the house, to learn more about his family. When showing Bod the room he lived in as a baby, Mr. Frost reveals that he actually is the Man Jack; Jack Frost is his full name.

Is Mr Frost a jack?

He runs down the stairs and tells Scarlett that Mr. Frost is actually the evil Jack who killed his family, and who now wants to kill him, and probably Scarlett too.

Is Jack Frost human in graveyard Book?

They're definitely people of some sort, but the novel identifies all the characters as people. They're not dead people, for sure. They don't seem to have any super-human physical abilities, other than maybe a sharp sense of smell.