While the Star Wars Rebels panel of season 4 is Saturday, a panel about Star Wars animation today at Celebration teased some things for season 4. First, we got the concept arts for Rex’s gear in season 4. He is going full on rebel gear and if you look at it, it seems to confirm that the rebel from ROTJ being Rex is becoming true. Filoni had said last year that he loved that theory and that he would make everything he could to make it happen, seems like he actually did. That concept art looks just like that rebel! During that panel, Filoni hinted at the return of Gregor and Wolffe for season 4.
— The Wookiee Gunner (@TWGsite) April 13, 2017