As with many other horror films of the era, the sounds of wolves howling in the night are unmistakably being made by a human being doing a poor imitation on a sound stage. The sound of a cat later on in the film is also noticeably human.
[Spanish dubbed version] In the original version, when Herman encounters Aunt Gussie, he hides behind a bush and does a "meow" which draws Aunt Gussie to the bushes looking for the cat. In the Spanish dubbed version, they neglected to put in the "meow" so there is no motivation for Aunt Gussie to go to the bushes.
When von Niemann shows Brettscheider a rosary he'd discovered, he calls it a "crucifix". Although a crucifix is part of a rosary, the entire piece is always called a rosary, not a crucifix.