The woman seen pulling Dr. Franklin on to the dance floor during the party is Richard Biggs' widow, Lori. They were engaged at the time this episode was being shot.
The Elvis impersonators showing up all of a sudden at customs were just one of many gags included throughout the show by J. Michael Straczynski as a means to break the tension. Other gags throughout the show included the teddy bear being shoved out an airlock, the doll without any "attributes", the "fasten then zip" conversation, etc.
This takes place from February 1 to February 15, 2261.