According to Carsen Gray, when she's speaking to Hook, what she's saying is Iroquois for "You are the life-stealer. You are evil. You smell bad. You smell of bear-poop. You are many moons old and ugly."
"Nana" was a Newfoundland, a breed particularly good with children, not a St. Bernard as used in the film. J.M. Barrie modeled Nana after his own dog, a Landseer Newfoundland. These dogs were very popular in Victorian England and were actually used to supervise children.
"Jas." is a standard abbreviation for the name James which is why the sign on Captain Hook's cabin door reads "Capt. Jas. Hook". This is taken directly from the book. It is not, as many viewers assume, a reference to Jason Isaacs.
Liam Aiken supposedly was set for an audition for the role of Peter Pan, however a few days before the audition producers found out that Aiken was only 12 at the time. The producers were looking for a young actor aged between 14-17.