You are taking a few facts and then trying to fit them into any/all records that you are coming across.
Start with the facts-James Nelson born 1841 Shankill, Belfast. Marriage gives father as James Nelson, publican. You’ve now
‘just discovered’ that his parents were born c1818 and c1821.
The above does
not mean that father James was a publican when son James was born in 1841, was listed in any directory, stayed in Shankill area and wasn’t employed in a pub (rather than actually running it). If James had lost contact with home then it’s possible his parents were already dead and he wasn’t aware that they were.
I found a James Nelson residing at 20 John Street Belfast..Publican..Wine Merchant..in the Belfast Directories..1831-2 Proni.If father James Nelson was born 1818 then he's not going to be a publican in his early teens.Now to James Nelson, publican-Going through some of the directories online you found 1843 Rodger Nelson publican at 23 Union St. living next to a James Nelson at 21 Union St.
http://www.lennonwylie.co.uk/alphanames1843N2Y.htmBy the time the 1852 directory was published both addresses are pubs run by James Magee & Robert Boyle.
“I have found James Nelson's father in Shankill Ireland..(Griffiths Valuation) Winetavern Street..Publican”Searching for James Nelson, Shankill Parish in Griffith’s brings up 11 entries-
the 1st one is James Nelson at 10 Winetavern St. with house offices and yard. It does not say publican. http://www.askaboutireland.ie/griffith-valuation/The printing date for that is 1860, so using the 1861 directory this seems to be the same James Nelson-
1861 Winetavern St. 10 James Nelson, white smith. http://www.lennonwylie.co.uk/wcomplete1861.htmHowever, going back to the online directories
there are no clear listings anywhere in Belfast for a James Nelson having a pub from 1843 onwards.There is still the problem that parents James and Agnes- other forms of Agnes are Nancy, Hannah and Ann(e)- could have died before the start of death registration in 1864. Unfortunately that makes it so much harder to pin down the parents.
Perhaps someday you will make contact with another branch of the family and be able to get further details but I'm going to leave this topic as I've already spent so much time on it.