As you, the earliest census finding James R. Ward and wife Mary/Mollie in Rockingham Va
Finding 1900,1910,1920 and 1930 with Mollie listed.
As you mentioned there were possibly 6 children, only three being listed as found as you posted.
In 1930. Mollie is found as mother in law with daughter Mollie L> Coffey and husband R. Wetzel Coffey. Mollie C. Ward is listed as widow age 75.
I did find one VA birth in Rockingham Va for a female WARD daughter of Jas. R. Ward and Mollie Ward for March 25 1888
This would not be the Molly L. Coffee in the 1930 census, with the dob being 10 yrs off.
So, that shows two more daughters added to the Ward family not found in records.
Someone has suggested that Molly C. Ward is Mary C. Offenbarger b. 1856 but the only connection is this Mary is living in Rockingham in 1870.
For some reason the 1910 VA census lists James and his parents being born in Alabama, even though the other census all list VA.
I did find where daughter Mollie L. Ward Coffey is buried in Rockingham Va. 1878-May 6, 1972 age 94 yrs.
If I find anything else, I will post.
Do you have any other info. of family to add?