I too have James Augustus Croal in my family tree, although I am not too sure where he fits in. He was in New York in 1918, married Edith Emptage in 1932 in Cardiff and died in 1957 - That's all I know of him.
I have several Croals who were born in Arbroath in the 18th century and then went to Georgetown. I do know that my GGG uncle was mayor of Georgetown and the main street (Croal Street) was named after him. Have a look at this PDF which shows my relationship with the Croals (My grandmother was a Croal). Let me know if there are any names you recognise. www.users.globalnet.co.uk/~rnewfie/Family_History/John%20CROAL.pdf