The child who talked to Jenna backstage played Jane Krakowski's son in Unbreakable Kimmy Schmidt (also created by Tina Fey)
The word "Nidurgängur" that the IKEA employee uses is in fact not a Swedish word. It does however look very similar to the Icelandic word "Niðurgangur" which translates as Diarrhea.
This is thr first time Jenna sings a "real" song on the show.