I would not worry too much about the Dylan fans, in a 10,000 seat-arena, you will hardly notice them among the crowds.
More worrisome is the fact that we do not know whether Bob and Mark will play together. My guess is that if Dylan makes the suggestion, Mark will be glad to accept. But it's probably Dylan's call and I'm not sure we will see them together with this two-band/two-set thing. The risk is that Mark takes his band and gets out of the venue after their performance. Hope I'm wrong.