When Liz and Jenna go on the Vontella Show, Jenna takes out her earrings, they are back in the next shot, and gone after that.
Jack refers to hosting a benefit concert like "We Are the World." However, "We Are the World" was a charity single, not a concert. Live Aid (1985) was the famous benefit concert that raised money for the same cause, the victims of the Ethiopian famine.