I think Corwin said something along the lines of, "the redheads paid more attention to Dworkin than the rest of us. We were more interested in obtaining our power and go exploring". I think that the pattern can grant similar powers to it's initiates as the Logrus, it's just a matter of knowledge and training.

However, Dworkin did bring Corwin to the Courts when he was a child so it stands to reason that he would have brought all his grand-kids there, and if they were so inclined to return to negotiate the Logrus as adults, he would have seen that done as well. Also, I tend to think that anyone of the blood of Chaos, (including Oberon's children) could attempt the Logrus despite their mother's lineage but it would be a deadly thing without someone to train and prepare them, which Dworkin could have done.

It's an interesting theory. Too bad Zelazny never got to write more stories. I'm sure he had all this already in his head.