Hi Sharon , the Isle of Man is a Crown Dependency , has its own Parliament - called the TYNWALD , supposedly the oldest Parliament in the World . Queen Elizabeth II is head of State as the "Lord of Man" , they say "they are not and have never been part of the UK" Obviously they are protected by the UK. As they are between Ireland and England , they have a big connection with both , and to a lesser degree Scotland. The biggest connection they have is Liverpool , England , as it has always been the major access point for the Manx people.
I believe your John is son of James Cool/Coole/Cooil/Cooill and Ann Kneal , John christened 29/10/1815 in Kirk(county) German , James & Ann married 19/5/1807 Kirk Michael. Appears after reading James will , he may have married Margaret Kermode 29/7/1856 Kirk Braddan.
Ann was buried 5/12/1848 aged 66 in Kirk German , and James 6/2/1861, aged 76 also in Kirk Braddan.
Ann's will indicates that children James, John and Jane were off the island as she left them money "if they come to the Island to seek it.
James will of 1861 , shows he was the Chief Constable of the town of Peel , Kirk German , he left John 90 pounds sterling - a lot of money in 1861 , same amount to his daughter Jane , who is shown as the wife of Charles Cain , Yeoman , City of London , Middlesex , Canada.
Cain is also a manx name. Rose is English , no sign of Sarah Ann Rose being born on the IOM.
Could not find John marrying Sarah Ann on the IOM, or in England