Daniel also didn't seem to know about the secret at all. He was a bit senile in 1840. I assume, in unaltered 1840, Daniel would have had a lucid moment at some point and remembered the secret, then told Gabriel about it (since Quentin had probably already been buried alive in the original version of 1840). Gabriel then told Edith who was to have passed it on to Edward. I always figured that even in the unaltered 1897, Edith STILL died before she had been able to tell Edward the secret. So perhaps Barnabas' presence merely "expedited" the inevitable.
