>>>Who was the Rayatz supposedly debating? A random am haaretz who happened to be a litvak who maybe said some nonsense?
Not getting into the whole discussion, but I would just like to clarify:
The debate was not with the Rebbe Rayatz. The Rayatz wrote what he heard from his grandfather (the Rebbe Maharash) about the debate in Minsk between the Alter Rebbe (baal hatanya) and the gedolei hamisnagdim of the city.
You can find an overview of the debate on Chabadpedia (as well as links to the original writing of the Rebbe Rayatz), by googling:
ויכוח מינסק
Or, in English, google: “the Debate in Minsk chabadorg”
(Though in the English it may be a bit hard to understand what’s going on)