Folklore.org has many stories about writing Lisa OS code in Pascal, about rewriting various pieces in assembly for the Macintosh, and developing apps in Pascal, but I can’t find any mention of actually writing any part of the original Mac system in Pascal.

Nothing you’ve quoted says otherwise. The closest is the very first sentence, but all it says is that Pascal was in use at Apple when the Macintosh project began, not that it was used for that project.