Hi Narelle

George's Baptism states his father is a Laborer (As spelt) , his marriage details show John is a Carter , which fits in as a Carrier. John Kneen 37 on 1861 Census Lodger 1 Big Well St, Douglas is a Carter, his is shown as unmarried.
I am not sure if you will ever be able to establish who Georges parents are.
FACTS
His DC shows parents John & Margaret , his Baptism agrees , and MC shows father John.
Cannot find a marriage of his parents , looked for any John and any Margaret marrying 1840-1854. and no obvious match.
Also looked for the marriage of all Kneens and same result.
Your George appears to be George Bryon son of Margaret Bryon on 1851 Census, but becomes her Grandson George Kneen in 1861 Census. The 1851 census was taken 30/3/1851, so if George was age 1 , he must have been born before 30/3/1850, but not baptised until 18/1/1852 - maybe because he was illegitimate - Frances may be able to comment on that.
George could be the illegitimate son of John K (Aged 30 in 1851) as he was in the same house , he still could be the son of Margaret Bryon (Aged 44 in 1851). John K could also be the Illegitimate son of Margaret Bryon maiden name Kneen.
I think your problem is, there is no paperwork to prove any of the above theories.
Cheers
David