All that I have found is speculation- the earliest of this type that I have found is the Ulster "Orange alphabet" which celebrates the activities of the Orange Order, a Protestant organisation founded in Co Armagh in 1795. It may actually be earlier as it describes the Battle of the Boyne in 1690. Coincidentally it seems that the Protestants began publishing "instructive" tutors for children at that same time which included the juvenile illustrated alphabet books we have all seen. I'm just trying to suss out the earliest occupational alphabet song- I suspect it to be the Sailor's because of its generally rhythmical cadence which could be used as a chantey; in Maine, the lumbermen, who often went to sea in the summer, adapted it for their work in the woods.