A brief glimpse of the DC fighting game Injustice 2 makes an appearance where William is shown playing as Poison Ivy (off-screen). In addition, there is an audio clip of Poison Ivy performing a supermove on another Poison Ivy in that same scene. Stephen Amell previously voiced the Arrow version in Injustice: Gods Among Us that appeared as an alternate skin for Green Arrow while Echo Kellum previously participated in the April 28, 2017 livestream of the Injustice 2 WatchTower.
At some point, Felicity said that she wouldn't ignore the option that Laurel came back from the dead because of previous experience with the Lance sisters, referring the many times Laurel's sister, Sara Lance, died (or at least thought to be dead) but then came back to life. The joke about Sara never stays dead was previously appeared in many episodes of DC's Legends of Tomorrow.
This episode takes place 5 months after the events of "Lian Yu".
Since this episode takes place 5 months after the events of "Lian Yu", and since the events of "Lian Yu" take place on May 17, 2017, that places the events of this episode sometime around October 17, 2017.