You are looking at a very wide period (1840 – 1860) during which Ireland changed enormously. In specific terms a huge amount happened, the Tithe War was not long over, the Famine occurred, a rail network developed through Tipp, the ‘Tipperary Bank’failed (a huge event, Sadleirs Bank, 1856, deficit £500k), the Young Ireland movement and its (failed) uprising took place, leading on to the IRB in 1858 and then Fenianism, etc. No part of Tipperary was untouched and some areas were key places in all those events. Despite a huge level of crime and violence against the person (Tipp & Limerick were by far the worst in the country 1840 - 1850) life went on – faction fights took place, race meetings were held (what is now Limerick Junction/Tipperary Racecourse actually commenced during the Famine) and people got on with their lives through extremely turbulent times.
It is impossible to state anything about your ancestors with any degree of certainty. Where they lived in Tipp also is very important – living on good arable land in the Glen of Aherlow is one thing, living near Cashel or Clonmel, or a garrison town like Templemore, or halfway up a mountain or on the edge of a bog, all would have been quite different.
The big ‘niggle’ I have is the size of their house (as also pointed out above) relative to the size of their land. I wonder did they have land rented elsewhere? Could the one-acre plot be a garden? People living on one-acre plots rarely had houses that size. One-acre lots generally had cabins, little better than mud huts. A single-storey cottage generally was 12 – 14 feet deep, so at 650sq.ft. that would mean 50 feet or four rooms long. By the standards of the day that would have been palatial for a labouring family. I’ve researched one family (1850) on the Tipp/Limerick border with 12 acres, some sub-let, and they had a two-roomed cottage. Parents dead, one teenage son and two in their 20's, they had a 30 year lease.
Typically an Irish estate had a pyramidal structure – at the top was the (often absent) landlord whose agent let to a middleman/men who in turn sublet to tenants who in turn sublet to smaller tenants, often relatives. Frequently there could be as many as five levels of tenants and sub-tenants between the landlord and the cottier / labourer. Each of those who sublet did so at a profit which inevitably meant that the poorest were paying the highest rent pro rata. Competition for land resulted in high rents and ever-decreasing farm sizes, thereby squeezing the peasantry to subsistence.
One-acre plot holders generally were ‘tenants at will’ i.e. they did not have paperwork/leases, and depended on a personal relationship with the immediate lessor. Some tenants actually preferred this arrangement.
There are several books available on the era but most are a bit ‘Oirish’ – e.g. ‘The Irish Sketchbook of 1842’ by William Makepeace Thackeray. It doesn’t have Tipp but is good background. Carleton’s ‘Stories of the Irish Peasantry’ is another. Hall’s Tour of Ireland – they went to Tipp in 1840 (?) is also worth looking at.