I agree about also having an open mind about whether or not the PONTCHARTRAIN was on the White River, as she may have been there at an earlier period, or she may not.
There are so many questions about the Confederate Navy that need to be answered, and I don't mean just on the Mississippi and her tributaries, but all over the world, inclusive of the cruisers. This (the details of the CSS PONTCHARTRAIN) is one small episode of that vast history of the CSN, and it is a pity that no one, to my knowledge, has attempted research on it. Despite the lack of a vast amount of CSN documentation, thanks to the destruction at Richmond, in April, 1865, there are other alternatives to obtaining information on various aspects of the CSN and her personnel (e.g. letters, diaries, etc., of the personnel involved, as well as some of the official documentation that was retained by CSN personnel, and are probably still in private hands, newspaper accounts, pension records, etc.), and these alternative sources should not be neglected. I am sure that sometime, somewhere, more documentation on the CSS PONTCHARTRAIN may surface, perhaps amongst papers held at the Arkansas state archives or similar facilities.
Very unfortunately, most Civil War researchers, students of the war, and other interested parties tend to concentrate on the activities and personnel of the Armies, and neglect completely, the Navies. And, as we all know, many of the activities of the Armies have been done to death (particularly Gettysburg).