Hello Dorothy,
Some early baptism details
1829 Winny of Walter and Bridget Joyce October 10 Liscarney
1843 John of Henry and Mary Joyce May14 Liscarney
1848 Catherine of Richard and Anne Joyce February 28 Liscarney
Poss 2nd marriage : 1856 Richard Joyce to Honoria McEvily August 11 Cuslough
1857 John of Richard and Honoria Joyce May 30 Liscarney
1859 James of Richard and Honor Joyce October 2 Liscarney
Walter would appear to be the oldest member in your tree and the remainder are likely to be his children. The problem with many of the parish records which will become available is there will be ineligible and missing pages. When searching the parish records your eye should also be tuned into looking at the names of sponsors and witnesses of non Joyce marriages, as these responsibilities were often gifted to other family members who may be named Joyce, especially where the connection/evidence may be ineligible or lost.
The Valuation would have been carried out within a year of its publication in 1855
If you click on the link http://bit.ly/1FnQkBE Liscarney is in the top left of screen. Zoom in and the parcel of land as you will see, 3 is unfortunately not parcelled up into 3 a,b,c or d. It is difficult to determine how the 83 acres was apportioned between the four tenants beyond the proportion of rent paid, but as two-thirds of the land looks extremely marginal they would appear to have only a small holding each of productive land. There is a group of five buildings which is most probably the location of Walter’s home and that of Harry/Henry and Patrick.
An article on the valuation http://www.leitrim-roscommon.com/GRIFFITH/Griffiths.PDF may be of some help in explaining the details. Coincidentally this is from a web site Roger is closely linked with.