My first guess was Sidney, since he’s the most associated to mirrors on this show, other than Ingrid. It would make sense to see him return, given his pre-established connection to Agrabah. And yes, Leah Fong is a new writer. The same writer that leaked part of 608’s outline on her Instagram, which spoiled that Rumbelle’s unborn child is a boy. Leah has since deleted the post.