In the beginning of the movie, the narrator states that accused witches were burned, hanged, and drowned. This is false. In Salem, 25 men, woman, and children died, 19 by hanging, 1 by being pressed to death with large rocks, and 5 died while in custody. Burning at the stake was only practiced in non-English speaking countries, like Germany. The "swimming test" is mostly an urban legend promoted centuries later. Instead the accused (again in Europe) were tested for their ability to stay afloat, suggesting that unholy persons would be rejected by the water.
At Jonah's desk, there is an issue of Fangoria (vol.7 #20), the horror magazine.
Keith David was cast in the film but he does not make an appearance in the final product.