Just a few points from Lumber Jack's posting.
The Margaret on the 1841 would have been born circa 1786-1791 and we don't know her maiden surname or even if she was married.
However, the An***try tree has Margaret Dickie b. about 1784 - so not too far out (although it also suggests that John married again

)
The Jean (could be called Janet) bpt. 1821 would have been born before that date - but a year earlier is unusual in those days. Is it coincidence that she was bpt. 2 Sept. 1821 and L-J's Janet was said to have been b. 20 Sept. 1820.
Based on my own ancestor's movements in Scotland in the 1820-40 period, Stewarton to south Glasgow is no distance at all - they used horse and cart.
My money's still on this Stewarton family with 9 children.
Gadget