It has occurred to me that I know of this family and the Currie half of it contains a trap. if you track Marion b. 1856, who married Donald Ewen MacDonald and settled at Glebe Cottage, Daliburgh, before her marriage you will find her at 468 Lochboisdale in the household of a married couple John Currie [Iain Ruadh mac Eoghainn] 1810-1892 and Catherine MacIntyre 1827-88. However, it was asecond marriage for both of them. John had already had Donald, Ewen, Marion b. 1842 who married Sam MacKenzie, Roderick and Margaret with his first wife. John and Catherine went on to have two children together, Mary 1862-4 and Mary 1865. However, Catherine had already had children with her first husband, confusingly also John Currie, in the Isle of Eriskay just off the South Uist coast. They were John 1851, Donald 1852, Isabella 1854, Marion 1856 who married Donald Ewen and Mary 1859-60.
That may possibly explain why they are difficult to trace but that Marion's was a Protestant marriage also suggests that someone, possibly Donald Ewen's father, the farm manager Donald MacDonald, was a resident of North Uist or even the mainland.
That makes no difference to the bardic descent. Just Google Niall or Cathal MacMhuirich or simply the surname. In 1800, Lachlan Mor MacMhuirich claimed to be 18th in descent from Muireadhach, the first of the family to move to Scotland in about 1213.