Well, ShaSha.....Since this is not the Walking Dead, doubt very much. The thing is, there is no drug to bring back someone from the dead, when they they have been dead for hours and hours, which EJ was. I figured that injection was a preservative, so the body could be transported to Italy, without deteriorating. He may have wanted it preserved in a glass coffin, so he could "see" his son all the time. ??
My thought about that is......since they film so far ahead....perhaps they thought, like they did with Bo, the actor would change his mind and come back after a 2-3 months off.
I guess we are getting some returnees. We do know that Chloe & Sonny are returning. And then we know Jack makes an appearance for 5 episodes, plus now we have heard Aiden is coming back. (And he also could be just a fantasy, a dream, new flashbacks.......who knows?