One of the children performing magic is Lagoon Boy
During a battle, Garth says "I summon the power of the tempest." Tempest is the last codename taken on by Garth in the comics, who was the original Aqualad.
The newspaper seen in Artemis and Paula's apartment featuring Bruce Wayne and Harvey Dent with the banner in the background reading "Future Site of the new Gotham Penitentiary" was reused from the Batman: The Animated Series episode "Pretty Poison"
The birthday for Earth-16's Jay Garrick is established as August 27th.
When aqualad is on his way to meet topo a girl performs a spell in Atlantean and then asks if it worked in English, after this spell everyone in Atlantis goes from speaking Atlantean to English