He has been a 'mystery person' in my mother's family (he was her grandfather), to whom various stories have accrued. However the RC records gave a start and there are various other clues I've been following. Here's the story as I've currently pieced it together.
He was born in 1830 in Dundee, baptised in January 1831 in the Catholic church (St Andrew's) in Dundee. His father was Michael Lynch, mother Margaret Haghey or maybe Harvey (as an earlier child James is born to Michael Linch and Margaret Harvy, and it could depend on how the priest or clerk heard the name when they wrote it). But his father died in 1834 - there is a burial for Michael Lynch in the Howff in Dundee, which I found thanks to the online transcriptions. (According to this, Michael Lynch was from Drogheda.)
Then, there is a Thomas Lynch in a household in Auchterhouse in the 1841 census. I had not known what to make of this, especially as the age - 12 - isn't right. However I've now talked to some people in Auchterhouse and Dundee, and learned that pauper children were routinely boarded out, some in neighbouring areas such as Auchterhouse. Today in Dundee, I've been looking at printed lists of pauper children (and others of the poor whom the parish council or kirk session took responsibility for). These aren't available for every year. However they are for 1836, 7, 8 and 9, and these show Thomas Lynch in Auchterhouse, first in the household of an Andrew Scott in Bonnettown, then with a Mrs Crichton in Kirkton, with a payment of eight shillings a month for him. There is also a George Lynch in the same household in 1836, then in 1837 he is listed with others who 'have been struck off the roll, or put to service, during the year'.
At this point, Thomas Lynch is an unusual name in Dundee. I think these are all the same person. The inconsistency of age could result simply from his being farmed out to Auchterhouse and then transferred to a second household there. The person giving information for the census in 1841 (Charlotte Chrichton as head of the household) might well not actually know - but would know he was bigger than the other children. Thomas knew (at least later) that wasn't right, may not have known his actual birth date but may have estimated it around 1831 or 2, and so from then on it's a bit fuzzy.
And, this Thomas Lynch would have ceased to be on the roll of the Dundee poor at around age 13 or 14, and then started in service, probably with a local farmer as the 'boy', the lowest in the pecking order. Alas, there aren't any more lists of poor until 1848, by which time Thomas is certainly too old to be mentioned on the roll, so I can't find the point at which he drops off it. He may then have moved around several farms, probably in the area of Auchterhouse, Glamis, Meigle, Kirriemuir, being fee-ed where there was work, and then in Kirriemuir met up with Euphemia Low, whom he seems to have married in 1850 - and in the 1851 census she's a linen weaver and he's an ag lab ... But they didn't stay together, and that's another story.
Or of course this whole construction could be quite wrong...
(And I still have to find him in 1861, and work out how/why he went from Angus to Glasgow where he turns up in 1868, with Dundee lass Margaret Cassidy.)
Jenny