The young actress who originally played Emily was terrified of the hospital setting in the second of this two-parts, Emily (1997), and as a result the producers had to recast the role and re-shoot all footage featuring the little girl. The young actress was Mecca Menard and she is in all the promotional photos of Christmas Carol. A few years later she played Young Natalie in Millennium (1996) (also created by Chris Carter).
One of the influences of this episode was the 1951 British adaptation of A Christmas Carol (1951) which starred Alastair Sim as Scrooge. Emily and her family were given the surname of Sim as a homage to that.
"Après mort" is French for "after death" and is sometimes used in business and legal terminology to refer to a payment or transaction made to or on behalf of a deceased person, typically for the purposes of life insurance payment or settling the affairs of a person's estate.
David Duchovny is largely absent in this episode because he was promoting Playing God (1997) with Angelina Jolie and Timothy Hutton at the time. Though he made a brief appearance in scene.