Zion being traded now is not a possibility, because he would have a low value. Dude just gets injured over and over again, so any team who would trade him, would know that it is likely that he would be injured again, so they are not going to really assume that he is going to stay healthy, hence they won't be willing to give much for him, doesn't make sense.
However, if they ever want to trade him after he stays health for a season, then we could see him do better, it is not going to be that much of a hard time at all, it would make sense and we could see him get a lot more value. The rest of the team should be open to trade, depending on what offer they get, it is not about rebuilding, it's about trading away someone to get someone better, they could give picks and players to get someone better.
Well, this is a risk that the Pelicans must take. You are right, he will have less value because of his injury history but there will be teams that might have better trainers that could come up with something and change his method. I really doubt it could happen in the Pelicans because he is being spoiled there. Yes, they input a clause in his new contract but there's really no change that is happening.
About if ever he is traded or not. The Pelicans could come up with a new plan and they could do what the Cavaliers or the Jazz did. Restarting their roster.
Input some veterans and focus on new players. The Pelicans could trade for draft picks and I am sure that will be a gem in the future.