In reference to the importance of Vincent in the final story line:
Cats are mostly associated with the royals in Egypt, but dogs do have an important place in that society, as hunting dogs, shepards, guard dogs and pets.
Dogs were reflected in their gods, including Anubis, who is shown with the head of a jackal. A jackal is a desert wild canine, a bottom feeder who would dig up graves. They used those observations to symbolize a dog's role in the after life.
Anubis was not a god of the dead, in the sense that he was the ruler of the underworld, he was the god who supervised the embalming and burial of the deceased and who guided the dead to the underworld. The symbol of the "dog" seems to have been associated with the notion of "guiding."
Wepwawet, another canine god, is often represented on the bough of a boat, leading the way. The name Wepwawet means "the one who opens the ways," I think this may describe Vincent when Ghost Christian told Vincent to wake up Jack after the original plane crash.
Once in the underworld, Anubis, assisted by the god Thoth, supervises the weighing of the heart of the deceased. Only when the deceased's heart was found to be in balance with all that was as it should be, Maat, was he introduced to Osiris.
Anubis was also the guardian of the necropolis or cemetery. He was also described as the "lord of the cave", where "cave" refers to the tomb.
