They are VAMPIRE!
If you watch the demo video again, you can clearly see that Mr. Howard casts no reflection in the Pre-War segment when looking at Codsworth's incredibly shiny and reflective body.
All joking aside, that is kind of disappointing. I always like seeing games that go the extra mile in giving your character a sense of solidity, particularly in the form of shadows and reflections. Especially when you can customize your character and have those shadows and reflections change to match that.