I will have to do some digging.I do not have any information concerning a John or Andrew in this time frame.I have no doubt that there must be a connection because all of my Kennair's are in the New Orleans area as well.
My John is suppose to be from Ireland, born Abt. 1831.Came to New Orleans ?I know of two sons, could be more children but do not know at the moment.His sons were Stephen (my ggrandfather ) and Edward. Perhaps your John is from Edward's line.
Will keep looking and if I find anything will let you know.