When the devil worshiper Carl Naft is brought back to life, he opens his eyes without any problem, when in fact the eyes of embalmed persons are glued shut and oftentimes inserted with plastic lenses to avoid sunken eyes during the funeral.
Tom is visibly breathing in the shots of his face and body, after he's been "killed" by the Coin.
Even in the 1980s, cemetery burials were required to be conducted using hermetically sealed caskets and placed in some type of grave liner, usually made of concrete. When the Satan worshipers rob the grave, two men would not be able to so easily access a grave and remove a casket.
Ryan says that Sylvan said that they're bringing back Hiberia. Up to that point, Ryan has never met Sylvan and has no idea what he did or didn't say.