First, factual errors, Barth is Reformed not Lutheran. Bonhoeffer is German Evangelical which was mostly Lutheran, but he certainly was much more Reformed than most German Lutherans would be comfortable with, and was criticized for it.
Second, Barth is certainly the best theologian in the neo-orthodox camp. Bonhoeffer was neo-orthodox as well but since he died so young, and without writing a lot of doctrinal theology (his writing was practical) it doesn't seem to matter much. But with Barth certainly the neo-orthodoxy, what he was revolting against and where he went with it controls his theology.
But in any case, Barth is the wrong place to be looking for insights into Lutheran theology.