"The Sultana Tragedy: America's Greatest Maritime Disaster" by Jerry Potter (1992) was offered by the History Book Club when it first came out. Amazon still offers this book. It is a comprehensive account of the sinking of the Sultana. I read this book more than twenty years ago. I also no longer own this book and I can not recall any of the details that will answer your questions about the legal aftermath of this incident. There were investigations and at least two people were court-martialed, but they were not convicted or had their conviction overturned. Again, the details are fuzzy in my mind, but they are all laid out in the book I cited.