I cannot prove that Evan Connet Williams was born in Saint Asaph because I cannot trace him on the 1901 census or 1911 census.
There is a family called Williams living at Cefn and they have a 7 year old son in 1894. The father is called Robert and the mother is Annie, but Evan was born in Abergele not Saint Asaph.
Record of Service Card held at Flintshire Record Office, Hawarden.
This card shows that Evan enlisted into the Rifle Brigade. His regimental number was 201306 and his address, Glasdyr, Pen y Cob, Saint Asaph. He died on 21st September 1918 and the card was signed by W Charles Jones but not dated.
Soldiers who Died in the Great War on Ancestry.co.uk
This document shows that Evan enlisted in Saint Asaph. He died in France/Flanders on 21st September 1918 in the Western European Theatre of War and his regimental number was formerly DM2/17080 Royal Army Service Cor, he was a Mechanical Transport Learner.
Medal Index Card and Medal Rolls WW1 on Ancestry.co.uk
These documents show that Evan, although he is named Avan on both records, was awarded The British War Medal and The Victory Medal. The Medal Roll also reveals that he enlisted into the Royal Army Service Corps, regimental number M2/170480 then was transferred to the 16th Battalion of the Rifle Brigade the again transferred to the 10th Battalion.
Unfortunately the sole Legatee is unclear but it may well be Mother Annie.
The Commonwealth War Graves Register shows that his parents were Mr and Mrs R Williams, Highfield Cottage, Pen y Cob, Saint Asaph.
I have searched the Welsh Newspapers to no avail
Evan Connett Williams is commemorated on the Vis-en-Artois Memorial, Pas de Calais, France.