Just wondering if the Mrs. Mary Morris mentioned in your question had ever been identified. My maternal grandmother was a Morris, and her family lived in and around Ada Valley, Adona, and surrounding area, but I cannot place who this could be from the death date you have presumed. Don't dismiss the fact that your Mrs. Mary Morris could have been visiting family in another location when the census was taken, and would have been counted elsewhere --- which could mean she wasn't dead then at all, just not in her own household with Drury Mack Allen and children.