Other mistake: When Lawrence is looking at his wound in the mirror, it has slightly healed. Later, when Sir John visits Lawrence in the asylum, he shows the bite mark he got from the feral child to Lawrence. Since Sir John is also a werewolf, the bite mark should not be there.
Other mistake: Gwen regrets getting Lawrence involved, saying that if she had never sent him that letter, he would still be in New York. She sent Lawrence a letter when Ben went missing in the theatrical version but, in the extended cut she went to tell him in person instead. Yet the "letter" line is retained in both versions even though it doesn't make sense in the latter.