Tradition was to marry in the bride’s church (after which she’d normally attend her husband’s). Greenbank Presbyterian church only has records from 1862. I don't know if that’s when it opened or whether there simply are no earlier records. Knowhead Presbyterian is nearby and has baptisms from 1826 and marriages from 1846, so might be worth checking their records for the family. (Statutory birth registration only started in 1864 so prior to that you need church baptism records, where they exist). The Kelly family may have been Church of Ireland. Muff COI records start in 1837. A copy of all 3 sets of records is held in PRONI in Belfast.
Griffiths Valuation shows Joseph Anderson having a farmhouse (plot 22a) and 39 acres of land. There were also 2 labourer’s cottages on the farm 22b (occupied by William Kelly) which had an outbuilding where perhaps he kept his materials, and 22c (occupied by John Anderson). 22a and 22c are marked on Griffiths maps, but unfortunately b is not. On Google Earth, I can see a clump of trees where 22a was (and perhaps the remains of some outbuildings) but the site does not look occupied to me. The nearest occupied property is probably what was 23b. That still looks to be a farm.
Births here for William, Joseph & Sarah Jane (all at Three Trees):
Informant was Eliza Kelly of Three Trees
Informant was Jane Kelly of Muff.
There were no Kellys or Andersons in three Trees in the 1901 census:
There was however a Kelly family in Muff, and the head was a shoemaker, so that would make you think there may be a connection. The family was Church of Ireland.
The wife’s maiden name was McKimm:
They married in 1880. Robert’s father was William a shoemaker. So he might be a brother to your William. Same family in 1911:
This might possibly be Fanny Anne Kelly’s death in Governor Rd, Londonderry in 1919. Robert was the informant. It would suggest the couple had moved down from Muff to the city by that date: