User blog comment:Thailog/Ep. 201 "Happy New Year!" discussion/@comment-24.241.237.119-20120430221504/@comment-1038387-20120501134245

Don't know about Artemis. But George Eads and Jason Spisak will be in episode 6 (Peter David confirmed it). I've read Kelly Hu would also return in that episode, but I couldn't find a source. But Stephanie Lemelin is back as the computer and sort-of-back as Catherine Cobert, so it seems likely Artemis will return too.

There's plenty of fan theories about what happened to Wally. He's either the new Flash, dead, lost his legs, married and on paternity leave, turned evil, or a combination of those. Relax, he's just not in this episode, people. They had to introduce a lot of new characters. It was already crowded.