In the matter of "Who burned Columbia?", there was ample evidence presented that looting and arson was committed by retreating confederates (specifically Texas Volunteers under the command Col. Wheeler) acting on the orders of General Wade Hampton before the Union army ever entered the city.
It is true that some stores were looted by Wheeler's retreating troops. Attempts were made by those troops under orders to remove government supplies so that the Federal troops would not have them, but they also looted.
Sherman, Logan, Howard vs. Hampton, Wheeler link
You posted a link. Here's another: Hampton, Beauregard, and eyewitnesses to the Columbia fire. This link says fires were out but were then started by Sherman's men.
Your link said Howard's testimony was consistent with Sherman's. Here is some anecdotal information about Hampton and Howard after the war [Link]:
Generals Hampton and Howard.
On one of Gen. O. O. Howard's visits to Columbia, during Reconstruction days, he met Gen. Hampton accidentally, in the presence of Major James G. Gibbes. The Major introduced the two Generals. Howard promptly put forward his one hand towards the Carolina General, who withheld his for a few seconds, saving, "I cannot take your hand, sir, until you retract your statement as to my connection with the burning of this city." "General Hampton," was the prompt reply, "I freely admit that I was mistaken in that matter ; and hope that now you will forgive and forget it." Hampton nodded and a hearty hand-shake resulted.
You posted a NYT link to the first column of Sherman's 1873 testimony. I took photographs of his testimony from that edition of the newspaper. As I remember, it took up over nine full columns of the paper. It took me 25 photographs to copy the whole article. Here is another part of the article you linked to [and here's a NYT link to the whole article, not just the first column]:
Q. -- You testified, a little while ago, that it was very likely they [Sherman's own men] might burn Columbia, and you permitted them, or your officers did -- permitted them to go about the town?
I could have had them stay in the ranks, but I would not have done it, under the circumstances, to save Columbia.
Q. -- Although you knew they were likely to burn Columbia, you would not restrain them to their ranks, even to save it?
A. -- No, Sir. I would not have done such harshness to my soldiers to save the whole town. They were men, and I was not going to treat them like slaves. ...
