William Creighton family

I'm looking for some details about a family that emigrated about 1846 to Canada.  The children were all born in Ireland, and there is the following quote from a Canadian source:

"Wm. Creighton, was a native of Tyrone, Ireland and came to Canada with all of his family, except James, in 1846.  William settled in Onondaga, his children, viz: Jane, Ann, Robert, Isabella, William (deceased), Margaret and Mary nearly all living in Haldemand County."

The children above are only the youngest members of the family, with the others as follows:

James Creighton (1818)

Ann (1827)

James Andrew (1829)

Thomas (1831)

Elizabeth (1832)

Robert Alexander Creighton (27 Mar 1835)

Isabella (21 Nov 1836)

Margaret (15 May 1838)

Mary (1842)

William (1846)

Above dates taken from the 1851/2 Upper Canada census

I have found James Creighton (the eldest son) in:

   Tithe Applotment Book, Carnteel Parish - 1827
CREIGHTON, Alexander         Sheanalurg [Shanalurg]

CREIGHTON, Daniel                Tullywinney

CREIGHTON, James                Lisdooart

CREIGHTON, James                Sheanalurg [Shanalurg]

CREIGHTON, John                    Sheanalurg [Shanalurg]

CREIGHTON, William               Tullywinney

AND -

Civil Marriage Record
Date of Marriage:    23-Apr-1846
Parish / District:    DUNGANNON         County:    TYRONE
    Husband                          Wife
Name:     James    Creighton        Isabella    Campbell
Address:     Lisdoart                        Mullaghmore
Occupation:     FARMER        
Age:     22        20
Status:     Bachelor (Previously unmarried)    Spinster (Previously unmarried)
    Husband's Father        Wife's Father
Name:     William    Creighton        Unknown    Campbell
Address:             
Occupation:     FARMER        FARMER
    Husband's Mother        Wife's Mother
Name:                     
Address:             
Occupation:             
    Witness 1                           Witness 2
Name:     Moses    Creighton        James    Campbell

A couple of William Creighton's children's baptisms appear to be in:

St. Kerog's Church, 1812-32, Baptisms from "Ulsterheart, an Ancient Irish Habitation" by the late Rev. Brett Ingram
William & Kate (Jervis) Eliza 1826, Thomas 1828

I have little idea about several questions like - Is the tithe record for James Creighton for two different James' or is it likely tht both properties were owned by one man?  Also, the birth dates for the two above are five or six years before the dates in Canadian records, but there is also a gap in the dates of birth of the children between James (b. 1818) and the rest of the family of almost 9 years, so I wondered if there is some possibility for another family to be the source of the Irish records above?

Finally, I wondered if there is any source that might give other connections or confirm the information from the Canadian records?