I'm gonna take a wild guess that Rahner and von Balthasar are not representative of how the Magisterium means Vatican II to be interpreted. (Indeed, it's probably a knock on the latter that he's in the same sentence with Rahner, and an unfair one at that.) In fact, according to my friend, Dr. Lawrence Feingold, a leading scholar and Catholic theologian, those views are almost entirely contrary to what Vatican II actually taught, assuming the hermeneutics of continuity. More investigation is certainly warranted. Even in the best form, the concept of "invincible ignorance" is a real stumbling-block to Protestants, whose missionary impulse and understanding of Jesus' exclusive claims prevents even the suggestion that a person might be declared just by God without hearing and accepting Jesus.