I see from his death certificate that Thomas died on 21.10.1865 at Black’s Court in Lurgan. (The informant was Jane McCavinagh. Do you know who she was?). I searched the Valuation Revision records for Black’s Court but his name doesn’t appear. That indicates either he didn't live there long enough to be listed by the Griffiths clerks or that he was lodging with someone else. His occupation was a labourer and they moved about all the time to follow the work. Very hard to trace them sometimes.
You don’t say what denomination the family was but I’ll assume RC. Lurgan is in Shankill RC parish. The RC baptism records start in 1822. Have you searched them for the family? Aghagallon RC records start in 1828.
The RC parish records are on-line free on the National Library site:
http://registers.nli.ie/parishes
The idea of a single or correct spelling for a surname or a place name is very much a recent phenomenon and before that, especially in Ireland, there was no consistency. Names were spelled phonetically and each variation was down to the whim of the particular person recording the information. You will often see the spelling change as the records go back. This rarely indicates a particular deliberate decision to alter the name nor even a mistake. Not everyone was literate, but even when they were, exact spelling simply wasn’t something they bothered about. In addition to varying the actual spelling, O’ or Mac prefixes were optional and were often omitted.
A part of the 1851 census for Aghagallon has survived. There was only one McC family in it. See:
http://www.census.nationalarchives.ie/pages/1851/Antrim/Upper_Massereene/Aghagallon/Montiaghs/29/
“Winer Babbins” is Bobbin winder, a skill in the linen making trade.
