Banquo is a fictional person. When Shakespeare wrote his play, MacBeth, Banquo was believed to be an historical person. Subsequent research has proved that there never was a Banquo. For greater detail of the complex set of legends in which he figures. see Space: Legendary Scottish Stewart Ancestry.
As a non-existent person, no parents, spouses, or children are linked to Banquo in the data field. Links to profiles of persons associated with Banquo, both real and legendary, are shown in the Research notes, below.
Banquo in Medieval History
In the time of Shakespeare (1565-1616) Banquo and Fleance were considered to be historical figures of great repute. King James I, based his claim to the throne in part on a descent from Banquo. 
Hector Boece's work, Scotorum Historiae (1526-7) is the first known record of Banquo and his son Fleance. Raphael Holinshead's Chronicles of England, Scotland and Ireland used Boece's work as a source. William Shakespeare, in turn often used Holinshead as a source for his plays, in Macbeth he borrows from several of the tales in that work. 
Boece's work may have been based on a now-lost source document of John Barbour entitled "The Stewartis Original". Barbour traced the origins of the Stewart clan back to Ninus, the founder of Nineveh. 
It was not uncommon in those days for aristocratic families to claim descent from mythological characters. The Scottish royal line that ended with the death of Alexander III in 1290 traced its lineage beyond the original Fergus Mor Mac Erc of Dalriada to a legendary character named Gaythelos, who engendered the Scottish race by marrying Scota, daughter of an Egyptian Pharaoh who reigned during the time of Moses. The early British kings were said to be descended from Brutus, great-grandson of Aeneas. It became a sort of contest among the royal families to claim the most impressive roots, and, in Scotland's case, it served to establish the separate origins of the Scottish people as against their nemesis, the English. 
Banquo's Legendary Place in Stuart Ancestry
Banquo was said to have been born in Lochaber, Scotland, circa 990 and died in 1043. In Shakespeare's play, he was killed by MacBeth. He was said to be a Thane, or chief, of Lochaber, a highland district in Inverness. As Thane, he served King Duncan. Banquo was said to have had a son, Fleance. 
In documented history, the Scottish House of Stuart is descended from Walter fitz Alan, the first High Steward of Scotland. In legend, Walter was the son of Fleance, son of Banquo, and Nesta verch Gruffydd, daughter of Welsh prince Gruffydd ap Llywelyn. 
Banquo in Shakespeare's MacBeth
In 1606, following the Union of the Crowns under which James VI of Scotland became also James I of England, Shakespeare wrote of Banquo in his famous drama "MacBeth". In the play, Banquo is depicted instead as Macbeth's rival; the role of fellow plotter passed to Lady Macbeth. In Holinshed's version, it is Banquo's son Fleance who meets up with the three weird sisters, the Godesses of Destiny. These are Holinshed's words from which Shakespeare would have borrowed the famous scene: "We promise greater benefits unto thee than unto him [i.e., MacBeth], for he shall reign indeed but with an unlucky end; neither shall he leave any issue behind him to succeed in his place, where contrarily thou indeed shall not reign at all, but of thee those shall be born which shall govern the Scottish kingdom by long order of continual descent."
In Shakespeare's version, MacBeth murders Banquo but not his son, Fleance. Shakespeare further flatters his new King, James VI of Scotland and I of England, by having the three sisters, or witches, show some of the line of Stewart kings carrying a triple scepter to symbolize their rule over England, Scotland and Ireland. 
Eyton and Round
J. Horace Round, the major genealogist who broke the myth of the Stewarts' Banquo ancestry, reported, "No less an authority on feudal genealogy than the late Mr. Eyton  (noted Shropshire historian) devoted himself to a special investigation on the subject of Alan "Fitz Flaald" and arrived at the conclusion
that, after all, [Alan] was a grandson of "Banquo, thane of Lochaber", whose son "Fleance" fled to England....'My belief is,' Mr. Eyton wrote, 'that the son of Fleance was named Alan...and that he whom the English called Alan Fitz Flaald was the person in question.'"  Round provides a pedigree of the early Dol family based on his research. This pedigree also appears on the Wikipedia page for Alan FitzFlaad. 
Round notes that as late as 1896, the Dictionary of National Biography, while admitting to some uncertainty in the earlier genealogy, noted attempts to trace the House of Stewart to "the Banquho of Boece and Shakespeare." 
Banquo flourished in the reign of King Duncan, and along with his sovereign was murdered by Macbeth in 1043, leaving an only son, Fleance. 
Fleance, to escape a like fate, fled to the Court of Llewellin ap Griffith, Prince of Wales, only, however, to meet at other hands the doom he had sought to shun at home. He is said to have fallen a victim within a few years of his arrival 1045 or 1047 to the jealousy of some of the Welsh lords whose ill-will he had incurred by his success in the favours of the Princess Nesta, the daughter of the Welsh Prince.
Walter, the son of Fleance by this lady, spent his youth at his grandfather's court, but, as he grew up, the animosity which had taken the father's life extended to the son, and Walter in his turn had also to seek safety in a foreign land.  Travelling first to the Court of Edward the Confessor, and next to that of Alan "the Red," Earl of Brittany, Walter ultimately attached himself to that Prince, to whom his mother Nesta is said to have been distantly related.  There in Brittany, following the example of his father, he won the favour of his protector's daughter, whom he married, and by whom he had a son, Alan.  Walter thereafter accompanied his father-in-law, the Earl of Brittany, to the invasion of England, but having for some reason incurred the displeasure of the Conqueror, he retired into Scotland, where he was received with favour by King Malcolm, who made him his Steward or Cup-bearer.  Walter is said to have died in 1093, and to have been succeeded by his son Alan, who, according to the same traditions, accompanied Godfrey de Bouillon to the Holy War, and was present at the capture of Jerusalem in 1099. Returning to Scotland in the reign of King Edgar, he was made Lord High Stewart, and dying in 1153, was succeeded by his son Walter, the first ancestor of the Stewarts who passes out of the region of tradition or hypothesis into the realm of sober and authentic History."
Directory of Banquo's Real and Legendary Associates
Kenneth III, thane of Lochaber married Dunclina, daughter of King Kenneth III of Scotland. Dunclina was a daughter of William Longspee, "first of that name [William], and second duke of Normandy."  Kenneth of Lochaber born about 0960 died about 1030 
Ragnhild Eriksdottir of Norway was the mother of kenneth.
Farquhar, Thane of Lochaber Farquhar was said to be the son of Kenneth Iii, Taoiseach of Lochaber and Dunclina Nic Cineada  Dunclina, wife of Kenneth was Princess of Scotland, born about 0960 Scotland
Banquo, Thane of Lochaber, murdered 1043. Fictional Person
Banquo, a fictional person, was said to have flourished in the reign of King Duncan, and along with his sovereign was murdered by Macbeth in 1043, leaving an only son, Fleance, who also was a fictional person. 
Banco of Lochaber, Thane, born Bef. 1018 in , Scotland; died Abt. 1040 in , England. He was the son of Murdoc of Lochaber and Princess of Dunclina of Scotland, Princess.  Born: before 1018 in Scotland, son of Murdoc of Lochaber and Dunclina of Scotland. 
Fleance. Fictional Person married Nesta, daughter of Llewelyn ap Griffith Llewelyn ap Gruffydd was a real Welsh king who had a real daughter Nest, who did not, however, marry Fleance or any other Scot. In other accounts, it is [[Griffyth-1|Guenta Filae Griffyth (995-1058) who was the daughter of Llewelyn and married Fleance in the form of Thane Flaald and became the mother of Alan Fitzflaald.
Walter, son of Fleance and Nesta, married the daughter of Alan, Earl of Brittany. died 1093
Alan, son of Walter and the daughter of the Earl of Brittany; accompanied Godfrey de Bouillon to Holy War, made Lord High Steward, and died in 1153. In fact, it was Alan FitzFlaald who was first a crusader and then an English lord; his son became the first Lord High Steward.
Walter, the first historical ancestor of the Stewarts.
Muldivana, wife of Banquo. Muldivana or Maud de Atholl is sometimes presented as Banquo's wife.  Rick Eaton wrote that Banquo's wife was the daughter of a King of Scotland--which one is unknown. 
Fleance is universally shown as Banquo's son. He is therefore also shown as the son of Muldivana, born 998.
FLEANCE, the youngest son of Banquo, somehow escaped the destruction which overcame the family when MacBeth, pushed into it by Lady MacBeth, according to the popular belief, murdered the thane of Lochaber and his three elder sons–Malcolm, Ferquhard and Kenneth. Fleance had two sisters who were not molested–Beatrice, married to MacDuff, thane of Fife; and Castisa, married to Frederick, the ancestor of the Urquharts. At first the youth hid himself into Cumberland [now a part of northwestern England, but at that time considered to be territory of Wales] to the court of Malcolm, "surnamed Canmore, son of the late king: but not judging himself safe there, or that prince not daring to afford him an asylum, he retired that of Griffith ap Llewellin, prince of North Wales." He was welcomed there; and in time he was married to Nesta, a daughter of Griffith. But "the great favors bestowed upon a stranger [foreigner] procured him so many enemies, that he fell a victim to their jealousy, in the twenty-fifth year of his age, in 1045, surviving his father only two years." 
Flaald is sometimes shown as the same person as Fleance. This conflation typically occurred after the Breton connection had been discovered but before the legend of Banquo and Fleance was abandoned, and was an attempt to graft the Scottish characftes onto the Breton characters.
↑ 3.03.13.2 George Edson, Article in Stewart Clan Magazine, Tome J, Volume 47, Number 7, January, 1970, pp. 77-80. Cited at Hidden Manuscripts
↑Rev. Robert William Eyton was the author of The Anquities of Shropshire (22 volumes). The Wikipedia reference provides links to online access to each volume. Accessed Jan 18, 2018 jhd
↑ 5.05.1 John Horace Round. Studies in Peerage and Family History. New York: Longmans Green; Westminster: Archibald Constable; 1901. The Origin of the Stewarts p. 115-146. Accessed December 28, 2017 jhd
Of Lochaber-1 and Banquo-1 are not ready to be merged because: At the moment they look like they are meant to be brothers. There are also several other profiles for Banquo who almost definitely is fictional, but at this stage not sure about Kenneth. I think though there needs to be more research before these profiles are merged.