I am a bit confused by your reply. I am not sure why you are listing on the Co Derry board if you are not sure that they came from Derry, somewhere. (Limavady, Ballykelly, Tamlaght Finlagan are all places in Co Londonderry. In fact Ballykelly and T/F are very close. Limavady would have been a very close larger town.
I am listing on the Co Derry board because William Laughlan b 15 Apr 1827 was born Co. Derry. I have never mentioned (or even heard of) the names you mentioned (Limavady, Ballykelly, Tamlaght Finlagan), The name Drumachose has been mentioned though. His father William Laughlan b about 1800 was simply born in Ireland. It is these two Laughlans I am trying to trace.
Census of Scotland 1861 shows that
William Laughland lived at 8 Moncrieff St, Paisley aged 33 (Miners Labourer), born in Ireland,
Jane, aged 26 born Renfrewshire, Paisley,
Samuel, Son aged 10, (Scholar), born Lanarkshire, Glasgow,
William John, Son aged 2, born Ayrshire, Auchinleck and
George Laughland, Son aged 6 months) born Renfrewshire, Paisley. Therefore William must have been born in Ireland in 1828, Jane in Paisley in 1835.
Samuel (whom we know nothing about) must have been born in 1851. I believe William came from County Derry, Ireland, but yet to confirm.
William was deceased prior to 1878 and Jane re-married a Mr. Baird.
Attached documents are all I have.
The marriage of William Laughlan (16 Oct 1855) shows his birth date as born April 15th 1827 at County Derry, Ireland.
If the birth took place in Co Londonderry then the births that others have found in the same decade and to parents with similar names are very worthy of further investigation.
Where do I look (I am in Australia and not familiar with Irish BDM)
Out of 4 William Lochlins, 3 were first sons if that helps, re naming patterns.