So William didn't marry in Bangor then, or did they have two marriage ceremonies??
Anyway, just supposing that the Samuel Moore, bachelor, 45 in 1911 was William John's father this is what I found:
Samuel Moore, born 1866, father William Moore, mother Mary Finley, who married in 1865 in Newtownards Presbyterian Church
and
just supposing that Jane Lightbody, spinster, age 51(?) in 1911 was his mother, this is what I have found:
Jane Lightbody, born 1869, father John, mother Ann Corne or Corns who were married in 1865 in Newtownards Church of Ireland.
I am sending you these details, as my subscription to Emerald Ancestors is going to expire soon, so just keep them in case they are relevant.
The only thing I can suggest is that you go onto the GRONI site and try to order William John's birth certificate. You have a good idea of when and where he was born. Give them all the info you have and see what they come up with.
As for Jane Lightbody's father John, he lived in Fisher's Hill,Bangor, Bangor Parish and
Samuel's father (probably William), he lived in Ballyskeagh Lower
Thiis is all deduction, as I would have to see their birth certificates to verify this.
RosemaryJoan