In the Baron's "dining room," running water, and sink with drain, did not exist in 1860/65. He would have had to use an outside well/ pump. Neither did electricity, with lights (to power his brain/eyes/hand experiment), until 1885.
When Frankenstein introduces his new assistant to his lab and shows him the brain, eyes, and arm, he states that the brain is responsible for moving the hand away from a flame; in actuality, the withdrawal reflex involves only the spinal cord-it does not involve the brain.
Peter Cushing's face being shown was not a goof. It was the face of the body he had made to resemble his own face that later had his brain transplanted to. It's ironic that the only successful monster was in fact Dr. Frankenstein himself.