Karen,
This looks to be your family in 1901:
http://www.census.nationalarchives.ie/pages/1901/Antrim/Raboo/Ballywill…
That gives you another child to the family (ie Mary Jane b c 1880).
In 1911:
http://www.census.nationalarchives.ie/pages/1911/Antrim/Raloo/Ballywillin/189854/
You?ll see from the 1911 census that in that year the couple had had 5 children, all of whom were still alive.
I see that there were 6 other McDowell households in Ballywillan at that time. You would expect most of them to be related:
http://www.census.nationalarchives.ie/pages/1901/Antrim/Raboo/Ballywillan/991399/
http://www.census.nationalarchives.ie/pages/1901/Antrim/Raboo/Ballywillan/991400/
http://www.census.nationalarchives.ie/pages/1901/Antrim/Raboo/Ballywillan/991386/
http://www.census.nationalarchives.ie/pages/1901/Antrim/Raboo/Ballywillan/991384/
http://www.census.nationalarchives.ie/pages/1901/Antrim/Raboo/Ballywillan/991387/
http://www.census.nationalarchives.ie/pages/1901/Antrim/Raboo/Ballywillan/991388/
Some of your family clearly attended Raloo Presbyterian church. Their baptisms start in 1842, marriages in 1841. There?s a copy of those records in PRONI (the public record office) in Belfast. Some of the other families were Non Subscribing Presbyterians (also known as Unitarians). Raloo NSP church has baptisms from 1859 and marriages from 1846, but the only copy is still held by the church. So neither church?s records are on-line anywhere. So some local research will be required to access them.
The 1876 marriage cert should give you James McDowell?s father?s name.
The PRONI wills site has 10 probate files for McDowells from Ballywillan. 5 of the wills are on line, 4 pre 1900 files have been destroyed and only the abstract survives (the summary). One will from 1949 is in paper format and so you would need to get a copy from PRONI.
http://applications.proni.gov.uk/DCAL_PRONI_WillsCalendar/WillsSearchResults.aspx
In addition, in their other paper records, PRONI has the following document:
Administration bond executed by Sarah McDowell and others administrators of the personal estate of Robert McDowell, Ballywillan, Co. Antrim. Dated 12th Oct 1880. PRONI ref: D300/1/5/784
James McDowell of Ballywillan signed the Ulster Covenant in 1912. You can see his signature on the Covenant site:
http://www.proni.gov.uk/index/search_the_archives/ulster_covenant.htm
You probably need to have a look at the tithe applotment records for Ballywillan to see who was on the various McDowell farms around 1830. The records for Co Antrim are not on-line, but there is a copy in PRONI.
Elwyn