The mule's name is Asterix which is the name of a famous French comic book character.
Alouette translates into "Lark" in English.
St Laurent (or Saint Laurence) is the patron saint school children, poor people, cooks and comedians.
The rifle Daryl uses is a Sharps rifle. They were used during the American Civil War and are "breech-loading" weapons meaning a metal cartridge is loaded from the breech end (at the trigger end of the barrel). This is in contrast to "muzzle-loaders" which are loaded from the front of the barrel and use a paper cartridge that contains the ball and powder where the paper serves as wadding to hold the powder in place. Both this Sharps rifle and Civil War era muzzle-loaders use a percussion cap to ignite the powder versus older flintlock or matchlock weapons.
The children were watching an episode of Mork & Mindy (1978) starring the late Robin Williams and Pam Dawber, which centers around the trials and tribulation of a woman and a chance encounter with an alien.