Frank Kogan

whether or not the social sciences "count" as something that can ever be truly incommensurable

Not sure what you mean by "can ever truly be incommensurable." Do you mean, "the stuff you're comparing is not coherent enough for us even to be able to see how incommensurable it is"? That seems like a complicated way of saying, "A field can't undergo a paradigm shift if it never had a paradigm [in the meaning of 'disciplinary matrix'] to begin with." But that doesn't mean there are no major shifts within any field that lacks an overall disciplinary matrix (such as, e.g., critical theory, lit theory, and so on). Change in such fields merely won't have the form of moving from Consensus A to Consensus B, since the consensuses aren't there. But we would be dogmatic in saying that a social science can never achieve consensus in the first place.

The Koganbot post you're looking about Kuhn contrasting the hard sciences and the social sciences is:

Kuhn 18: A difference between the natural sciences and the social sciences.

But Kuhn is not saying that a social science can never ever get itself together, he's merely saying that the ongoing debates over "fundamentals" are a sign that, e.g., sociologists and psychologists haven't pulled it together. If they do (or have started to) pull it together, you could say that prior to the pulling-together those fields were in their pre-paradigm state, and that now they're developing paradigms (in both senses of the term). A question for you to ponder is what would that "pulling together" consist of. It's not just a bunch of people deciding to agree on something-or-other.