Thank you so much for your research. In answer to the question regarding witnesses to Appolonia Williams and William Jones marriage, they were Grace Jones and Robert Williams, possibly siblings of the bride and groom, but maybe not! They all made their mark, I don't think anyone in the family could read or write in those days.
I have documentation to show that my great grandfather, William Jones born about 1841, was alive in 1910 and in the Union Workhouse, I have found him there on the 1911 census too, listed as married and former mason. However, in the 1881 census, Appolonia is listed as a boarder, living with her children, and a widow. On the 1891 and 1901 census she is living with her grown up children at 4 Glanciedra Court, Mountain St., Carnarvon and is listed as married. In 1911 she is living at 51 Mountain St. with her son and his family (enumerator has terrible handwriting) and it is stated that she is a widow. I think there was great shame in being in the workhouse, which is why she may have said she was widowed. The 1899 death date for William Jones would have made him born in 1829, not 1841, so that can't be correct. I believe he died on 3 Feb. 1912 at Union House (Carnarvontraders and BDM) . Thank you for pointing out that 1861 census records for Canarvon are missing, that explains some gaps but it is still the 1841 and 1851 census for Appolonia and William that I am missing and evidence of their birth or baptism and parents.