Finding this quite confusing.
In timeline order (green from your post, blue from SP, purple from FreeCEN, red from FindMyPast)
1819 Joseph Monro, son of Collin Monro and Isabel Webster, born in Boyndie
1824 Isabella Webster, wife of Colin Munro, dies in Boyndie
1826 John, son of Colin Munro and Isabella Webster, born in Boyndie
1827 Colin Monro marries Janet Mustard in Banff (the original one, not the one in Canada!)
1832 Colin Munro and Janet Mustard emigrate to Canada
1852 John Munro marries Jessie Davidson in Inverurie
1861 John Munro, 37, born ?Benny, in census in Inverurie with wife Janet and children
1871 John Munro, 47, born Boyndie, in census in Inverurie with wife Jessie and children
1881 John Munro, 56, born Boyndie, in census in Inverurie with wife Janet and children
1891 John Munro, husband of Jessie Davidson, dies in Scotland
Leaving aside the fact that you seem to be suggesting that John was born 2 years after Isabella died, did Colin really leave John behind when he emigrated? And his twin brother George? What about big brother Joseph?
An age of 37 in 1861 and 47 in 1871, if accurate, would mean that he was born in 1823 or 1824, which would fit better with his mother dying when he was born or soon afterwards.
John and Janet/Jessie's children were Jane(t), Isabella, John, Margaret, Catherine Webster, William Allan, James Grant, Alexander Sutherland, George, Charles and Robert. No Colin, as you would expect if his father was Colin. Unless of course John was so resentful of being left behind when his father emigrated that he refused to name one of his sons Colin.