I can help you a little bit, but I'm a little unsure of how this William J. NULL fits in. Maybe someone else can help.
There are a lot of William NULLs in Missouri, and several William J. NULLs. I can trace mine back to a William NULL in Jefferson County. I belive the initial "J" stands for "Jefferson" because one of my ancestors was listed as William Jefferson NULL IV.
The 1900 census lists a William J. NULL family in Miller County, Missouri, Richwood Township, Supervisor's District #149, Enumerator's District #86, Sheet 3A.
Here is a partial listing of the family, including name, relationship, month and year of birth, age, state of birth, father's state of birth and mother's state of birth:
Null, William J. Head April 1856 44Missouri Missouri Missouri LovieyWife July 186634IowaOhioKentucky Harry R.SonJan 188614Missouri Missouri Iowa Charles A. SonJan 188911Missouri Missouri Iowa MyrtleDauFeb 18919Missouri Missouri Iowa BulaDauOct 18927Missouri Missouri Iowa ArchieSonSept 18945Missouri Missouri Iowa NULL, EvalineHead May 183367Missouri Missouri Missouri
The census also indicates that William and Loviey (sp?) were married 15 years (They must have married in the first half of 1885) and that they had seven children, five of whom survived.
It's interesting that they were enumerated right next to Evaline NULL, a widow. I have a Michael NULL married first to Eliza Julia Hildebrand and second to Eveline Hensley on February 25, 1855 in Franklin County, Missouri. Michael died in 1899. But, I don't have a William as a son from either marriage. So, I'm not certain where this William J. NULL fits in. Maybe someone else can help us out.