Matthew Lillard posted on Twitter and Instagram that he is working on a new series. No news other than that single comment.* His Instagram came with a video that included Frank Welker, Kate Micucci, and Kevin Conroy (aka Batman).
* Update: On the Instagram post, Lillard hashtagged Michael Ryan, which reveals one crew member in some capacity (which is more than likely writer/story editor).
* Update 2: The series will be called Scooby-Doo! Guess Who? (which might imply that Kevin Conroy could play Batman, unless it's referring to the villain.)