He was the son of James Millikin and Celicia (or Alina) Margaret Millikin. In 1901 the family lived in house 21, Drumharvey, Co. Tyrone. James was a Bank Cashier. Wm was not recorded on the 1901 census form for this address although he would have been aged 4. A sister, Marion (aged 2) is recorded.
In 1911 the family lived in house 13, Marsden Gardens, Clifton Ward, Belfast. The father is still a Bank Cashier. The family consists of James, Cecilia, Elizabeth (16), William (14), Marion (12) and Kathleen (11).
On ‘Ulster Day’, Saturday, 28th September 1912, Millikin’s father signed the Ulster Covenant at the Old Town Hall, Belfast.
Another image of Millikin in this link:
Northern Bank Golf Outing - May 1951