Very much a passing of the torch...legacy thing, and a homage to the stories that have had Hippolyta as Wonder Woman in World War II with the Justice Society, etc.
Nothing yet on Chloe and Ollie. When asked by people on Twitter, Q has replied that they will return when he is ready for them. He's kind of been cryptic regarding them, making some fans believe that there has been an editorial embargo imposed due to "Arrow"...but he's not confirmed that at all. It is my guess they will return at the end of the season.