Many stories of Walkelin and William have been conflated, including accounts of the Crusade. Walkelin survives the Crusade, as noted by a number of charters and fines.  The Itinerarium Peregrinorum et Gesta Regis Ricardi mentions in a couple of places, including Acre deaths, the "comes de Ferrariis". In a few other places, including Normans joining the expedition, distinguishing himself, and being well liked by Richard I, it mentions "Walchelinus de Ferrariis". It does not call "Walchelinus" the "comes de Ferrariis". Some accounts now have Walkelin dying at Acre, or have William being a favourite of Richard I, making these passages refer to one person.
At some point there has been one or more really bad merges and Walkelin or Walchelin de Ferrieres, the Norman ancestor of the Ferrers family has been merged with his great great grandson, William de Ferrers, 3rd Earl of Derby, with probably another Walchelin de Ferrers as well. More work will have to be done to decide which wives and children belong to which profile.
Given the amount of biography it seems more logical leave this profile as William, 3rd Earl of Derby and change the first name and preferred name, and recreate a profile for the 2(?) Walchelin profiles, if other ones don't already exist.
Please handle these changes with care, so that more mistakes aren't made
ThankyouAtkinson-107 16:53, 3 March 2017 (EST)
Biography of William, 3rd Earl
1140 Birth and Parents
He was born in 1140, the son of Robert de Ferrers and Margaret de Peveril 
William succeeded his father [before 1160) as Earl [of Derby]. 
Marriage to Sibyl
He married, as her first husband, Sibyl de Briouse, daughter of William II de Brouse, Lord of Bramber & his wife Bertha of Hereford who died after 5 Feb 1228.
Sibyl may have married secondly as his second wife, Adam de Port. 
Regarding The history and antiquities of the county of Buckingham, pg 252-253 pedigree chart:
It is Robert II, 2nd Earl of Derby, son of Robert I and Hawise, who marries Margaret Peverel. They have sons William and Walcheline.
It is that William, 3rd Earl of Derby, who marries Sybil de Braose. They have children William, 4th Earl of Derby, Robert, Milisent, and Agatha.
He was a member of the Knights Templar, Knight and Crusader. "From the year of our Lord's incarnation 1164, the fourth year of the papacy of Alexander, the tenth of the most illustrious Henry, king of the English, in the presence of the same king, was made this remembrance or recognition of a certain part of the customs, liberties, and dignities of his predecessors, that is to say of King Henry his grandfather and others, which ought to be observed and held in the kingdom." ... "these being present:" ... "William earl of Ferrers" 
1180 Breedon Priory
He founded a priory at Breedon, co. Leicester, about 1180. 
Benefactor to Churches
"Though he was not responsible for the foundation of any religious house, William, the 3rd earl, was a generous benefactor to the church, increasing the endowments of Breedon and Tutbury Priories; making grants to the Hospital of St. Lazarus, the Knights Hospitallers, and the monks of St. Denis in France; and, in this deed, extending his father's gift to Garendon Abbey — which was later doubled by his son."
"Moreover I William for the love of God and for the souls of my father and mother and of all my predecessors, and for the good of my soul and that of Sybil my wife and those of our children, ..."
"... with the consent of William my son, so that they may hold it in pure and perpetual alms freely and quietly and exempt from all secular services. And I and my heirs will warrant to the aforesaid abbey and monks the aforesaid land to hold with pasture by the aforesaid liberty, as our free alms. By these witnesses : Countess Sybil, Robert de Ferrers brother of the Earl, etc., Luke, then Steward, William de Rideware, Hugh de Thornd', William Mauveisini, William, son of the earl and Henry and Robert his brothers, Jurdan de Thoc, Henry the vintner, William the clerk of Lee, with many others."
William, his son and successor, being forbidden by Henry II. to use the title of Earl of Nottingham, assumed by his father, joined the king's sons in their rebellion against him, and plundered and burned the town of Nottingham; but when he saw his castle of Tutbury closely besieged by a strong body of royalists, aided by a band of Welshmen, and the king marching against him with a second army, he thought it best to avert the approaching storm, and submitted himself to the king at Northampton. 
He donated property to Tutbury Priory for the soul of his wife Sybil and his ancestors Henry de Ferrar, his grandfather Robert and his father Robert. 
"Robert de Ferrars, the last Earl of Derby, confirmed all the benefactions of his ancestors by charter, but by him the priory was pulled down in the year 1260, and was not rebuilt till theyear 1307, no doubt by the Earl of Lancaster." 
He participated in the Third Crusade and died during the siege of Acre. The Annals of Margan record the death in 1190 of “Willelmus comes Ferrariis”. Matthew Paris records the death at Acre in 1191 of "comes de Ferariis". A letter dated 21 Oct 1190, recording the arrival of the archbishop of Canterbury at Tyre, names “...comes de Ferreres...” among those who had died [in Palestine]. 
He subsequently accompanied Richard Cœur de Lion to the Holy Land, and died at the siege of Acre, in 1191, leaving, by Sibilla de Braose, his wife, four sons.
"Each day He increased and strengthened the number of the Faithful. Princes, dukes, counts and great numbers of lesser degree streamed together from various parts of the globe. These are their names: The earl of Ferrers [William de Ferrers I, earl of Derby]; ..." 
"The historical and diplomatic interest of charters from the third crusade of lesser men than the king lies in their rarity. Howden's list of the crusaders who died at Acre or at Jaffa or on the journey included some of the greatest men in the land - Robert, earl of Leicester, William Ferrers, earl of Derby, and Nigel de Mowbray among the barons, ..." 
William was killed in battle at Acre before 21 October 1190. 
William, died 22 Sep 1247). “Willielmus comes de Ferrariis, filius Willielmi comitis de Ferrariis” donated property to Tutbury Priory, for the soul of “Agnetis uxoris meæ”, by undated charter. He succeeded his father in 1190 as Earl of Derby. 
Millicent. A manuscript narrating the foundation of Wigmore Abbey records that “Milesaunt filia --- comitis Derbeyæ” was the first wife of “domini Rogeri”. This has not been corroborated from other primary sources, but, if it is correct, her father must have been William 3rd Earl of Derby. m as his first wife, ROGER [III] de Mortimer, son of HUGH [II] de Mortimer & his wife Matilda de Rumilly (-before 19 Aug 1214, bur Wigmore).] 
Petronilla de Ferrers, died after her husband, buried at Stone. "---" [name omitted] made a fine "de voluntate et assensu Milisente q fuit ux Hervei Bagot", the order specifying that "ipsa Milisenta" donated "in vita sua tercia parte toci terre sue…cum Petronilla sorore com de Ferrar" whom "Herveus de Stafford" married, dated 1214. m (1214 or before) HERVEY Bagot of Stafford, son of HERVEY Bagot & his wife Millicent de Stafford (-[Nov 1236/12 May 1237], bur Stone). 
Robert de Ferrers, died 4 Dec 1225. A writ ordered pardon of a fine that "Robert de Ferrers had made…with the king’s father" for marrying "Joan daughter of William of Buckland", dated 9 May 1221. The Annals of Dunstable record that “Robertus de Ferrariis” died in 1225. His precise relationship with the family of the Earls of Derby has not yet been ascertained. However, from a chronological point of view it is possible that he was the son of Earl William. m as her first husband, JOANNA de Bocland, daughter of WILLIAM de Bocland & his wife Matilda de Say (-before 16 Nov 1251). "Robertus de Ferrariis" paid a fine for marrying "Johanna filia Willelmi de Boclaund cum terris…que fuerunt eiusdem Willelmi", with saving for "matri ipsius Johanne q fuit ux predicti Willelmi…dote et maritagio suo", dated [Apr] 1216. Bracton lists a claim by "Willelmus de Aurenches et Matillis uxor eius, Johannes de Bouilla et Hauissia uxor eius" against "Robertum de Ferrariis et Johannam uxorem eius", dated 1218, for "hereditate Willelmi de Boclonde patris earum", noting that "Matillis et Cecilia [error for Hawisia] sunt sorores sororis [error for uxoris] sue [=predicti Willelmi]". A writ ordered pardon of a fine that "Robert de Ferrers had made…with the king’s father" for marrying "Joan daughter of William of Buckland", dated 9 May 1221. She married secondly Simon d’Avranches. A table in The Complete Peerage shows that she married secondly Geoffrey d’Avranches. This is incorrect, her actual second husband being Geoffrey’s brother Simon d’Avranches, as shown by documents shown in Avranches chapter of the document UNTITLED ENGLISH NOBILITY. A writ dated 16 Nov "37 Hen III", after the death of "Joan de Ferres alias de Ferrers", names as her heir "John de Everenges alias de Averenges her son aged 23".] 
↑ Leicestershire and Rutland Notes and Queries and Antiquarian Gleaner: Vol 2, p 191 
Walkeline de Ferrers (d.c. 1040), 11th century Seigneur of Ferrières-Saint-Hilaire and father of Henry de Ferrers.
This sounds like Walchelin de Ferriers profile. They are 2 different people. Walkeline sons Henry and William came to England with William the Conqueror in 1066