La Croix calls Currie "Frank", but when he writes his name in the diary, he calls him "Robert"
The cursed pen works inconsistently. It appears to require the knowledge of the user, So when the killer tries to use the pen on Micki and Ryan, it fails because he doesn't know who they really are. But later it is stated the real Brothers Matthew and Simon died. The killer didn't know who they were, either, so why did they die? Or did every Brother Matthew and Simon in the world die from a tarantula bite?