Frank Logan referenced the Donn coat when he donated the Forbes/Pendel coat to the Chicago Historical Society the same year:

Spurious letters purporting to have been written by Mr[s]. Lincoln have appeared, which makes it easier for me to understand how a grave error, to say the least, has been committed in Philadelphia regarding a coat, which if ever Mr. Lincoln's, could not have been the one worn by him that night, as the above testimony, I think, substantiates. (LOGAN)

The coat failed to reach a minimum bid at auction and was returned to the Donn heirs.

New York Times article, February 21, 1924.
A second frock coat associated with Lincoln's assassination was placed on auction in Philadelphia in 1924 by the family of Alphonse Donn, another White House doorkeeper during the Lincoln administration.

Both men were originally assigned to the White House as Metropolitan Police guards in November 1864. Donn and Pendel found favor with Mary Lincoln and were quickly promoted to positions as doorkeepers. Pendel petitioned Mrs. Lincoln on behalf of Donn two weeks before the assassination. Two of Donn's relatives had been drafted, and their wives were distraught. Draftees had the option of hiring a substitute to take their place in the army, but Donn's relatives could not afford replacements. Pendel described the incident in his autobiography:

Dunn said to me one day, "Tommy, won't you go upstairs and see Mrs. Lincoln and ask if these men may have more time in which to get a substitute?" I said, "Dunn, why don't you go up and see her yourself?" He said, "Tommy, I don't like to go." He pleaded with me so earnestly that I finally went upstairs and saw Mrs. Lincoln for him. She told me to go in and see the chief clerk and have the document drawn up; then I was to bring it in to her, and she would sign it. I did so, and before ten days expired peace was proclaimed. Consequently, Alfonso was happy and the two men who would otherwise have been compelled to leave their wives were also happy, I presume.

Alphonse Donn (also spelled Dunn) and Thomas Pendel had parallel careers during the Lincoln administration.

Donn spent the evening out with Tad on the night his father was assassinated. Pendel comforted Tad after he returned home, lying beside him in bed until Tad fell asleep. Pendel claimed that Tad often begged to spend evenings with him:

"Tom Pen, I would like to go to the theatre to-night. Won't you go upstairs and ask mamma if I can go?" I would go to her and say, "Mrs. Lincoln, won't you let Tad go to the theatre tonight?" And she would say, "No." Then I would plead with her and say, "Now, Mrs. Lincoln, let him go." "Will you go with him, Pendleton?" "Yes, madam, I will, and take good care of him." "All right, Pendleton; then he can go."

Tad (Thomas) Lincoln, Meserve Collection, Chicago Historical Society.

Both Donn and Pendel befriended Tad Lincoln, the President's twelve-year-old son.
Mary Todd Lincoln in 1861 (ICHi-11228).