The 1851 census of Nelson Parish, Northumberland Co., NB also has a household:

Wilson John M Husband 60 Scotch Ferryman 1817
Wilson Euphemia F Wife 60 Scotch 1817
Wilson Jane F Daughter 29 Scotch Mantrea? Maker Born Col
Wilson Mary F Daughter 27 Scotch Mantrea? Maker Born Col
Wilson Wm M Son 22 Scotch Lumberer Born Col
Wilson Elizabeth F Daughter 20 Scotch Born Col
Wilson Jesse F Daughter 18 Scotch Born Col
Wilson James M Son 15 Scotch Born Col
Young Marg t F Daughter 32 Scotch Born Col
Young Mary I. F Granddaughter 12 Scotch Born Col
McEachran Ronald M Lodger 50 Scotch Labourer 1820
Armstrong John M Servant 19 Scotch Ferryman 1845
King John M Lodger 25 Irish Shoemaker Born Col

The scarcity of the name, King, in Nelson Parish in 1851 suggests that John King may have been Philip’s brother; and, therefore, that John and Euphemia Wilson may have been Ellen’s parents. The difficulty is, however, that Ellen arrived in NB in 1841 while John and Euphemia arrived in 1817. The only other King’s in the parish at the time were:

King Philip M Head 28 Irish Shipwright Born Col Ord Health
King Ellen F Wife 26 Irish 1841 Ord Health
King Francis M Son 5 Irish Born Col Ord Health
King Thomas M Son 4 weeks Irish Born Col Ord Health

so a connection seems worth investigating.
While there appears to have been a fair number of King’s amongst the Loyalists in 1783 (possibly of the Salem, MA family), what seems to be of interest is a grant made in Buctouche (in what was then Northumberland Co., but now, I believe, in Kent Co.) to numerous persons, including Benjamin (98 acres), Francis (118 acres) and Vancislos (128 acres) King. These appear to have been brothers. Most of the other grantees were Acadian; and these three King’s may have been as well. It was not unusual for Irish immigrants to marry Acadiennes, and some Irish names in NB are often assumed to be Acadian.
‘Vancilos’ King may be the ‘Francilos’ King who was granted land in Newcastle Parish, Northumberland Co., NB (500 acres) 15FEB1810. Other grantees were Israel (500) and Michael (500) King. Again, the other grantees were Acadian. Francis King was granted 200 acres 8AUG1815 in Wellington Parish, Northumberland (again, now Kent CoCo., NB. Francis King, Jr. was given 200 acres in Wellington Parish 17DEC1824. This may have been the same Francis granted 75 in Chatham Parish, Northumberland Co., NB 20JUN1840. John King (possibly the John in 1851) was granted 50 acres in Chatham Parish, Northumberland Co., NB 3OCT1846. In later years, King’s are found in Wellington Parish, Kent Co., NB (including a L’aimable/L’amable King; again suggesting the Acadian connection); in Restigouche Co. (including a Francis King) and other locations in Northumberland Co. These appear to suggest that there was a King family in the Northumberland Co. area; without have to look too closely (yet) at King families in other areas. Grants were made to King’s in Northumberland Co. as late as 1964.
Looking at petitions, solely in Northumberland Co., the earliest was John King 1788; suggesting a member of the loyalist families seeking land northwards. More significant is Francis King (1820), Philip King (1849) and Edward King (1859.) In each case, the petitioner was alone suggesting someone fairly recently married seeking land for a growing family.
Checking the directories for Northumberland Co., in 1865 there were:

King, Edward Water St. Newcastle Northumberland Laborer
King, Joseph Backwoods road Chatham Northumberland Farmer
King, Mathias Backwoods road Chatham Northumberland Farmer
King, Mrs Elizabeth Cunard n Church Chatham Northumberland

In 1867:

King, Edward Water Newcastle Northumberland laborer
King, Elizabeth Mrs. Cunard n Church Chatham Northumberland
King, Joseph Backwoods Road Chatham Northumberland farmer
King, Mathias Backwoods Road Chatham Northumberland farmer King, Philip - Douglastown Northumberland labourer
King, Thomas - Douglastown Northumberland shoemaker

In 1871 there were:

King, Joseph - Douglassfield Chatham Northumberland Farmer
King, Mathius - Douglassfield Chatham Northumberland Farmer
King, Philip - Rosebank Newcastle Northumberland Farmer

In Chatham Parish, in 1851, there were two households close together, presumably neighbours.

King Thomas M Head 48 Irish Farmer (prop) 1822
King Ann F Wife 30 Irish 1847
Brackin Michl M Step son 12 Irish 1847
Brackin Sylvester M Step son 8 Irish 1847

King Francis M Head 60 Irish Farmer (prop) 1820
King Joseph M Son 30 Farmer Birth
King Mathias M Son 17 Farmer Birth

Speculation suggests that Thomas and Francis were brothers, Thomas had m. a widow and Francis may be the Francis, Jr. That one arrived 1822 and the other arrived 1820 does not mean they did not arrive together; only that they have different recollections of when. It is not unusual for the same members of a family (which obviously arrived together) to give different immigration dates. The best that can be said is that both arrived ca. 1821; give or take. What is particularly notable is that this King family is NOT a Loyalist family.
An intriguing entry in the 1851 census of Chatham Parish is:

King Philip M Head 27 Irish Ship Wright Birth
King Ellen F Wife 27 Irish 1841
King Francis M Son 4 Birth
King Thomas M Son 1/12 Birth

Obviously the same family as in Nelson Parish, with slight variations. Thomas, in Nelson, is given as age 4 weeks, and in Chatham as age 1 month. This suggests that both returns were taken at almost the same time. In Nelson, Philip is age 28 and Ellen is age 26; while her both are age 27; suggesting different (but knowledgeable) informants. the conclusion is that they had residences in both parishes; and it is not all that unusual for persons to be twice enumerated (or not at all, for that matter.) Another factor is that Philip seems to be connected to the King family in the above land grants and petitions.
In 1881, in Newcastle Parish, Northumberland Co., NB, is what appears to have been another Philip King, b. Ireland ca. 1811, and his wife, ‘Letilia’, b. Ireland ca. 1831. A son is Francis (b. ca. 1850.) In fact, Francis appears to have been a popular name and in the NB census of 1881, and the US census of 1880, there a numerous Francis Kings. Many in the US are from Canada, and some from NB. There is even, in 1881, a Francis King b. NB ca. 1835 in Lancashire. England. I suspect that sorting out Francis King’s may be an ordeal.
The senior Francis, probably progenitor of this family, was b. Co. Cavan, Ireland ca. 1794, and d. Douglasfield Settlement, Northumberland Co., NB 11OCT1861 age 67 years. This would also appear to be the Francis b. ca. 1791 in 1851. It is also possible that the Mrs. Elizabeth King in Chatham in 1865 and 1867 was his wife. It is very likely that the elder Francis was Philip’s father.

PHILIP KING b. NB ca. 1823-4, m. ELLEN Wilson (b. ca. 1824-5.)
children:
1. FRANCIS KING b. ca. 1846
2. THOMAS KING b. 1851
3. HARRIET ANN KING b. ca. NOV1858, d. Beaubair’s Island, Northumberland Co., NB 20AUG1864 age 5 years and 9 months

Thomas