The point is that Scripturally they are not infallible, and you have failed to give a coherent answer to my basic questions, thus my response must wait.
There is circularity in this claim. Yes, the 2nd Century based its claims on the doctrines than came from the Apostles, and the fact that they were in writing substantiated their historicity. But the fact that they had been preserved seems to indicate they were preserved because they substantiated the claims of those who preserved them. Doctrinally, they are evidence, but they are a collection, not a treatise or a catechism, or a book of disciple. Like any library, they tells as much about the owner as they do about the writers.