Question: how is Nicholas Llewelyn Davies and Peter and Wendy related?

Context articles: Llewelyn Davies boys
Jack Llewelyn Davies
William Llewelyn Davies
Nicholas Llewelyn Davies
Peter and Alice
J. M. Barrie
Sylvia Llewelyn Davies
Peter Llewelyn Davies
Peter and Wendy
George Llewelyn Davies

The Davies boys (the family only used the double surname Llewelyn Davies in formal contexts) were the sons of Arthur (1863–1907) and Sylvia Llewelyn Davies (1866–1910), the daughter of the French-born cartoonist and writer George du Maurier, and sister of actor Gerald du Maurier.
 The boys were the first cousins of Gerald's daughter, the author Daphne du Maurier.
 They were the inspiration for J. M. Barrie's Peter Pan, in which several of the characters were named after them.
John "Jack" Llewelyn Davies (11 September 1894 – 17 September 1959) was the second eldest of the Llewelyn Davies boys befriended by Peter Pan creator J. M. Barrie, and one of the inspirations for the boy characters in the story of Peter Pan.
 He served in the Royal Navy during World War I.
 He was the first cousin of the English writer Daphne du Maurier.
Sir William Llewelyn Davies (born William Davies, and adding "Llewelyn" after marrying Gwen Llewelyn) (11 October 1887 – 11 November 1952) was chief librarian of the National Library of Wales, Aberystwyth from 1930 until his death.
Nicholas "Nico" Llewelyn Davies (24 November 1903 – 14 October 1980) was the youngest of the Llewelyn Davies boys, who were the inspiration for J. M. Barrie's Peter Pan and the Lost Boys.
 He was only a year old when "Peter Pan, or The Boy Who Wouldn't Grow Up" hit the stage in 1904, and as such was not a primary inspiration for the characters of Peter and the Lost Boys.
 However he was eight years old when the novel adaptation "Peter and Wendy" was published, and in later editions of the play, the character Michael Darling's middle name was changed to "Nicholas."
 He was the first cousin of the English writer Daphne du Maurier.
Peter and Alice is a play by American writer John Logan based on the meeting of 80-year-old Alice Liddell and Peter Llewelyn Davies, then in his thirties, in a London bookshop in 1932, at the opening of a Lewis Carroll exhibition.
 The production was directed by Michael Grandage and was performed by Judi Dench as Alice and Ben Whishaw as Peter.
Sir James Matthew Barrie, 1st Baronet, {'1': ", '2': ", '3': ", '4': "} ( ; 9 May 1860 19 June 1937) was a Scottish novelist and playwright, best remembered today as the creator of Peter Pan.
 He was born and educated in Scotland but moved to London, where he wrote a number of successful novels and plays.
 There he met the Llewelyn Davies boys, who inspired him to write about a baby boy who has magical adventures in Kensington Gardens (included in "The Little White Bird"), then to write "Peter Pan, or The Boy Who Wouldn't Grow Up", a "fairy play" about an ageless boy and an ordinary girl named Wendy who have adventures in the fantasy setting of Neverland.
Sylvia Jocelyn Llewelyn Davies (25 November 1866 – 27 August 1910), "née" Sylvia du Maurier, was the mother of the boys who were the inspiration for the stories of Peter Pan by J. M. Barrie.
 She was the daughter of cartoonist and writer George du Maurier and his wife Emma Wightwick, the elder sister to actor Gerald du Maurier, the aunt of novelists Angela and Daphne du Maurier and a great-granddaughter of Mary Anne Clarke, royal mistress of Prince Frederick, Duke of York and Albany.
Peter Llewelyn Davies MC (25 February 1897 – 5 April 1960) was the middle of five sons of Arthur and Sylvia Llewelyn Davies, one of the Llewelyn Davies boys befriended and later informally adopted by J. M. Barrie.
 Barrie publicly identified him as the source of the name for the title character in his play "Peter Pan, or The Boy Who Wouldn't Grow Up".
 This public identification as "the original Peter Pan" plagued Davies throughout his life, which ended in suicide.
 He was the first cousin of the English writer Daphne du Maurier.
Peter Pan; or, the Boy Who Wouldn't Grow Up or Peter and Wendy is J. M. Barrie's most famous work, in the form of a 1904 play and a 1911 novel.
 Both versions tell the story of Peter Pan, a mischievous yet innocent little boy who can fly, and has many adventures on the island of Neverland that is inhabited by mermaids, fairies, Native Americans and pirates.
 Peter has many stories involving Wendy Darling and her two brothers, his fairy Tinker Bell, the Lost Boys, and the pirate Captain Hook.
 The play and novel were inspired by Barrie's friendship with the Llewelyn Davies family.
 Barrie continued to revise the play for years after its debut until publication of the play script in 1928.
George Llewelyn Davies (20 July 1893 - 15 March 1915) was the eldest son of Arthur and Sylvia Llewelyn Davies.
 Along with his four younger brothers, George was the inspiration for playwright J. M. Barrie's characters of Peter Pan and the Lost Boys.
 The character of Mr. George Darling was named after him.
 He was killed in action in the First World War.
 He was the first cousin of the English writer Daphne du Maurier.