Unfortunately, I do not have the information you were looking for, but I know a family of Niblocks, in Salisbury, Rowan, County, NC, that would be interested in knowing if there is a connection.
The only reason I came across this is because I am one of the Rock Hill Craigs, and may be kin to the Niblock/Craig family you mentioned.
An aunt told me that she went to a cemetery near Cleveland, NC. Don't know the church's name, but it is something to do with Third Creek.
She says all the information is listed upon one stone. She mentioned a William, George and Levi Niblock. This particular stone does not mention where William was born in Scotland.
If there is a connection, maybe we can help you find the information you are seeking. Best regards, Christine Craig