What you say is almost certainly true about the confusion between the Henry & John Wright pairings. And this conundrum in Morant has been vetted many times before with few different outcomes. Henry and John of the 5 May 1609 death date (Vol 2, p 121) get pushed into the 15th century on the justification that 5 May 1609 should be 5 May 1509 death date for John, Vol 1, p 185 clearly states that the John Wright who possessed White Notely had father named John and wife Ann Sulliard, so could not be the Henry Wright-son John Wright pair mentioned in Vol 2, p 122). Therefore Anna Whitebread married this fifteenth century Henry Wright and not the one buried in White Notely in 1618. Ergo, the Henry Wright buried in White Notely 1618 was most likely the infant son of John Wright & wife Ann Sulliard who had died November 1617 birthing him.
In summary, what we have are the following written signposts from Morant:
1. A John Wright dying 5 May 1609 connected only vaguely to White Notely and with a father named Henry (Morant Vol 2, P 121-122)
2. A John Wright dying 25 May 1608 connected to Kelvedon Hall & White Notely with a father named John Wright who was Lord of the Manor of Kelvedon Hall.(Morant Vol 1, p 185)
3. A report that Anne Sulliard, wife of John Wright of Kelvedon Hall and White Notely Hall died in childbirth 28 November 1617.
4. A parish register entry that has a Henry Wright being buried in White Notely 24 Apr 1618 and presumed married to Agnes Whitebread of White Notely.
5. Reports of recusancy by both and Agnes Wright and an Ann Wright in the years 1625 and '26 respectively.
Going into further detail in Morant:
From Morant, Vol 1, p 185: John Wright, Esq. d. possessed of Kelvedon Hall Estate 5 Oct 1551 together with Wife Olive. (I have a copy of both their wills and probate record) Son and heir of John (d. 1551), John (the Elder) died 10 Oct 1563 also possessed of the Kelvedon Hall Estate. John Wright (d. 1563) had wife named Joan and son and heir named John, "....who held this maner of Kelvedon, with its rights, members and appertenances, of Robert Lord Rich....etc. ...He had also the maner of White Notely, and the advowson of Upminster Church &tc. He died 25 May 1608 leaving --- John Wright, his son, aged 21 years (w) who married Anne one of the daughters of Sir Edward Sulliard of Flemyngs in Runwell in this county and had by her 3 sons and 4 daughters. She dyed in childbirth 28 November 1617 and he himself 4 March 1661.----John Wright, Esq., their eldest son and heir, departed this life 31 May 1656, aged 46, and Francis his wife, eldest daughter of Philip Waldegrave of Borley in this county, Esq., 25 December 1658 in the 44th year of her age. They had two sons, John and Philip, and one daughter, Frances."
Morant goes on to list the Elder line's lineage right up to 1768. This entire rendition squares with what is listed in the Visitations of Essex (1552 & 1634) regarding this family lineage and thereby puts into relief the question of who was the Henry Wright father of John Wright who died 5 May 1609 (and the John Wright as well) who are mentioned by Morant later in his tome under the White Notely heading. Most of our esteemed Kelvedon Hatch genealogy researches of the past (Rodney P. Wright, Curtis Wright, Rev. Milton Wright circa 1910) have concluded that the references to Henry Wright and John Wright refer to Morant's awareness of the Essex Visitations of 1552 and place him in the earliest generation of this family and not as a reference to a Henry Wright buried in White Notely 24 Apr 1618. This may be because they never found the burial record in White Notely for Henry Wright or simply dismissed it as the infant son of Anne (nee Sulliard) Wright. Having missed or dismissed this bit of information, and the possibility that Agnes Whitebread married this later day White Notely Henry Wright and not our alleged Henry Wright (b. 1424) our esteemed elder genealogists reported Morant's information as a typographical date error and put Henry and John at the head of the Kelvedon Hatch Wright line.
Morant, Vol 2, pp 121-122.
To be continued.