Title is French for "I'll Never Forget You".
The song Durant has Henri sing is "Dans l'eau de la claire fontaine" which is French for "In the water of the clear fountain". It is a traditional French song and has dates back to 1604, while it was frequently sung for children is has a rather adult theme: lost love. The song is about a young woman bathing in a fountain who has lost her lover, she hears the song of a nightingale perched on a rose bush, which reminds her she lost her lover because she failed to give him a rosebud, and wishes she still had it to give to him. "Rosebud" being a euphemism for a girl's virginity, so she is wishing that she was still a virgin so she could give that gift to her true love. A rather ironic choice of song since Lily has just lost her true love, and unlike the woman in the song, has no chance of ever getting him back again.
Bleeding Kansas, also called Bloody Kansas or the Border Wars, actually happened. It was a series of violent civil confrontations in the Kansas Territory, and partly in western Missouri, between 1854 and 1859. The conflicts were caused by increasingly heated and hostile debates over the legality of slavery in Kansas, which is why it is also known as The Tragic Prelude to the Civil War. The period of violence came to head on October 16, 1859 when abolitionist John Brown led a raid on the armory at Harper's Ferry, Virginia, the armory is where most of the weapons and munitions for the United States military was manufactured and stored. Brown, who was already wanted in Kansas and Missouri for theft of slaves and murdering slave owners, did so in an attempt to incite a slave rebellion in the Southern states, he led a force of 22 men in an attempt to gain control of the armory. They succeeded for a short time but were quickly defeated by a force of United States Marines commanded by Colonel Robert E. Lee (the future Confederate general) and led by First Lieutenant Israel Green (who went on to be a major in the Confederate Marines). During the fight to retake the armory ten of Brown's men were killed, seven were captured (including Brown) and five escaped; there were two Marine casualties as well: one injury and one fatality. Brown was placed under military arrest and charged with high treason against the Commonwealth of Virginia, murder and inciting rebellion, he was found guilty of all charges and was executed on December 2, 1859; the other six that were captured were also convicted and hanged.
Actress April Telek is a Canadian actress and was Miss Canada 1994. She plays the prostitute Nell, but this isn't the first time she's played an old west prostitute, she also played one in Frontierland (2011), an episode of Supernatural (2005). The transcontinental railroad is also a part of that series' plot, Durant is making the railroad route as twisted and long as possible to get as much money from the government as he can. In Supernatural's story the railroad's twisted route in Kansas is to form part of a giant devil's trap around a cemetery that contains a doorway to Hell. Railroad ties are made of iron, which is something demons cannot cross, so the transcontinental railroad forms part of a series of rail lines that form a circle around this doorway.