Syndrome is supposedly dead in the DHBM timeline (DHBM takes place after the first Incredibles), yet he still happened to be playable. By this logic, Bing Bong CAN become playable, but (obviously) probably won’t.
(Also, if Anger III sees this, WE ARE NOT THE DEVELOPERS, THIS IS SIMPLY SPECULATION. JUST BECAUSE BING BONG IS LIKELY DOESN’T MEAN HE’S CONFIRMED. NOW STOP SPAMMING OR ELSE I’LL HAVE TO SIC LOUTRE ON YOU!)