2. Even if Bonhoeffer gave up on the pacifistic ideology, we could find a number of individuals who clung to non-violence in the face of great evil (a good starting list can be found in this article).
3. I'm not familiar with the evidence, so I will emphasize that you must look into this further if it is of interest. Some believe (as in this article) that Bonhoeffer did not actually throw off his pacifistic ideology at the end of his life. They use documentation of his arrest, his own writings, and other evidence to make the case that Bonhoeffer held onto his pacifistic ideology until the end. If he did, that certainly doesn't prove pacifism right, but it would help to at least undercut this argument a little more.