Gerry went to school in Glasgow, Scotland. Peter's family seem to hail from Drogheda in Eire. No idea where JW was raised, so I don't see any connection between the 3 men.
https://www.independent.ie/irish-news/parents-of-madeline-mccann-make-first-trip-back-to-donegal-since-her-disappearance-28823741.htmlGerry's father was from the province of Donegal.
"Gerry McCann's father John was from the village of St Johnston, where the family owned a pub. Maddie posed for pictures outside the premises during the April 2007 holiday.
Mr McCann also has a large number of relatives in the Dungloe area.
The family have rented a cottage there and are said to have been overwhelmed by the warm reception during their trip.
"People here know Gerry and Kate well and we're just letting him get on with their holiday without any fuss," said one local resident last night. "They're one of us.""
Thet are just words to me, I don't know the area.