Neal McDonough (Oliver Queen/Green Arrow) would later play Damien Darhk in Arrow (2012), a live-action TV show about Green Arrow.
Oliver Queen's cell phone includes the names of Bruce (Bruce Wayne/Batman), Wally (Wally West/Flash), Diana (Diana Prince/Wonder Woman), Clark (Clark Kent/Superman), Dinah (Dinah Lance/Black Canary), and Mort (Mort Weisinger the creator of Green Arrow).
Princess Perdita would later appear in Young Justice (2010) as Perdita Vladak, with Ariel Winter reprising the role briefly before Hynden Walch took over.
Sylvester the Sky Man is known in DC Comics as the hero Skyman (Sylvester Pemberton).