I’ll try and help with Griffiths.
Griffiths Valuation shows James and Daniel Sullivan jointly renting plot 1 in Gortavehy East. It comprises 3 houses, offices (ie outbuildings) and agricultural land amounting to 115 Acres, 1 rood and 32 perches. (40 perches in a rood, 4 roods in an acre). Measurement is in statute acres, as opposed to the tithe applotment records which are in Irish acres, which are bigger. The next column shows the value of the land (for local tax purposes), then the buildings and the final column is the total of the two. Pounds shillings & pence. (12 pence in a shilling and 20 shillings in a Pound).
James & Daniel had a cottage on their land (plot 1d) which they sublet to William Sheehan. He was probably a labourer on their farm, and the small patch of land would be where he grew his own potatoes. His home consisted of a house and garden sized at 1 rood and 5 perches. Buildings and land both valued at 5 shillings each. Total 10.
Plot 3 is land only. No buildings. Mountain grazing which is shared between John, James and Daniel Sullivan. 302 acres, 2 roods & 19 perches valued at £11 10 shillings.
Landlord for plots 1,2 & 3 was Eugene McCarthy. he might have been the actual owner or he might have been a middle man.
In the 1901 census there were 3 Sullivan farms (headed by 2 Eugenes and a Cornelius). Plus 2 labourers’ cottages:
https://www.census.nationalarchives.ie/pages/1901/Cork/Caherbarnagh/Gortavehy_East/
If you click on the household return for each property you can learn a little more about each one. So for example, house number 1 had 8 outbuildings, the farmhouse had walls made of brick or stone, it had a tiled or slated roof (as opposed to thatch or wood); there were 5 rooms, 5 windows at the front of the house. If you then go to the outbuilding return you will find there was a stable, cow house, calf house, dairy, 2 piggeries, a fowl house and a shed.
Note that the numbers in the censuses were the enumerators private numbering system and do not relate to the plot numbers in Griffiths (unless by accident). And the house numbers used in the 1901 census are not necessarily the same as those in the 1911.