I agree that Stephen was a brave martyr but we have no evidence that his death had anything to do with his belief in the resurrection. Moreover neither Stephen or Antipas were ever named as witnesses to the resurrected Jesus so, like with Paul – who I already addressed, these people cannot be used as evidence for the resurrection – which was exactly what Mr. Andrews argument was supposed to be doing. Recall that, in his opening statement, Mr. Andrews acknowledged the important distinction between ‘dying for a belief’ and dying for something you would have been in a position to know the truth about – so it’s unfortunate to see him abandoning this distinction in order to broaden the pool of people whose deaths he can appeal to for his argument.
As to Acts 12 – yes it does record the death of James, the brother of John. It claims that he was killed by Herod by the sword – no further details are given.