For Ann(e) Farrell B 1850 +/- 1 yr, Co. Wicklow, with a father forenamed Tho(mas), I found 1 rcd, 1849, Glendalough RC parish.
For Mary Farrell B 1849 +/- 2 yrs, ditto, I found 1 rcd, 1851, also in Glendalough RC parish.
Marriage rcds for Co. Wicklow either didn't survive, or haven't been transcribed yet.
For Thomas Farrell B 1823 +/- 4 yrs, Co. Wicklow, with the father's forename unknown, I found 6 rcds: 1821 Delganey CI, 1822 Kilaveney, 1822 Glendalough, 1822 Dunlavin, 1826 Baltinglass, and 1827 Hacketstown RC parishes. Father's respective forenames are Gabiel, Laurence, Patrick, John, n/r, and Thomas.
For Mary O'Neil B 1827 ditto, I found 47 rcds - too many to easily summarize here. Perhaps the B rcds for the children will identify persons who could be her parents.
This is more than you requested. Hope it helps. Suggest you Email: email@example.com to see if/when marriage rcds will be added. Good luck.