John Wilson Rice was a brother of my great great grandfather Robert Rice (d. 1856). The other brothers were James Rice, Hugh Rice and William Rice (and there may have been others), and there was also at least one sister, Mary Anne, who died as an infant in the 1820s and was buried at Old Rashee Cemetery, Ballyclare, County Antrim, in the same grave where her parents Robert Rice (c. 1789-1851) and Agnes Rice (died 1836), were subsequently buried. The latter Robert Rice was a son of James Rice and Anne/Agnes (nee Wilson) of Donnybrook, Dublin; his maternal grandfather was Robert Wilson of Cogry, Ballyclare, and his maternal uncles, James Wilson, Thomas Wilson and Robert Wilson of Cogry, were among the leading landowning gentry in the Ballyclare area in the early to mid-19th century. The last of the male-line Wilsons of Cogry was John Wilson (d. 1857), who was Robert Rice's first cousin, and it was presumably from him that John Wilson Rice got his name.
In 1854, John Wilson Rice married his first cousin Anna Martha (O') Rorke, only daughter of James Rorke and Mary Anne Rice (who was a daughter of James Rice and Anne/Agnes Wilson and a sister of Robert Rice of Ballyclare) of Middle Mountjoy Street, Dublin, and Anna Martha Rice survived into the 20th century and is recorded in the 1901 census residing in Sligo. A copy of her will is available for consultation in the National Archives in Dublin.
I hope this information is useful.