Hi, I am researching the same period. John Ouseley Kearney was in The New South Wales Corps from before 1806. He transferred to The Royal African Corps in 1810. He was reputed to have resigned his commission in Sierra Leone circa 1817. He worked there for a while (with his brother, William) under Governor MacCarthy before changing to become a notorious slave trader. He had fled by 1821. I believe this John married in 1812 and had children born in Ennis, Co. Clare in 1814 and 1815 so like the family you are researching they must have had leave or had their wives with them
I too had been wondering about the father(s) before seeing you had a very similar story.
I still have not found John's military records. I wonder if he was ever caught - would his military record mention this ?