Upon review, Hartmanis and Stearns appear to have come closest to my work. I would recommend readers take a look at Algebraic Structure Theory of Sequential Machines (1966) prior to my paper to get a background motivation for my treatment of the subject. The idea of partition pairs in that textbook coincides with epimorphism classes in the Sierpinski topos.

So basically, all I am doing is updating that prior work and turning it into a Topos Structure Theory of Sequential Machines. I arrived at the concept of partition pairs independently through the Sierpinski topos. Hartmans & Stearns came up with the same idea for its engineering applications. It often happens that when an idea is good, it tends to crop up independently in multiple different places.