A bit belated, but Charles McConochie was born on 24 Feb 1833 in Canongate Edinburgh, son of Robert McConachie and Janet Murdoch. He also appears in the 1851 Census, aged about 19, in Greenock (Scotland), as a lodger while an Apprentice Engineer. He appears (in Cardiff) with his wife Mary Ann and the rest of the family in the 1871 and 1881 Census and died in the last quarter of 1888 aged 55.
The only tentative record for John is the birth of a John McConochie to Robert McConochie and Janet McMurchy on 22 September 1922, in Greenock. Janet and Robert had been married on 1 Dec 1821. Can't find a marriage record for Robert and Janet Murdoch, so can't ascertain if Charles was the son of a second marriage of Robert.