Edwin Booth was exceedingly famous, and should be the main character of this movie. John Wilkes Booth should be a supporting character, even though his dastardly deed certainly rocked the career of Edwin.
Asia Booth (sister of Edwin and John) was a character in this movie. In real life, she wrote a biography of her brother John. It is interesting to read. She does not condone John's infamous bad deed, but she explains John's history from childhood.
There was at least one more sibling in this family: Junius Booth, Jr.
John Wilkes Booth had previously been employed by Laura Keene in her acting company, she who had produced the play "Our American Cousin" the night Lincoln was shot. One year before, John Wilkes lost his job with her. He was a very handsome man, and fancied himself somewhat of a matinée idol.
Laura Keene was America's first female theatrical producer and director, and I feel that she fired John Wilkes due to his self-centered and egotistical demands. Perhaps he was no team player, and was miffed for being fired by a woman.
He had a year to hatch his conspiracy for the demise of Lincoln and other cabinet members, including time to gather his co-conspirators. Thankfully, part of the plan was botched. The other cabinet members escaped being killed. Lincoln had several tickets, including a pair for General and Mrs. U.S. Grant. The Grants declined, as did several other invitees. This is why the Lincolns were the only couple in their box.
Lincoln had just been re-elected. The war was over. The South had lost. John Wilkes Booth had a twisted idea that he must make amends for the 'bad' state of things. The rest is history.
Too bad this helped put Edwin Booth's career into eclipse for awhile. Edwin was so talented, though, that he actually managed to salvage what was left of his career and put it back on track.