I love Zaza, but I am not sure why Atlanta would trade him.
Ultimately though, I think the answer for the C's is already on the roster. They just need Wilcox and Darko to get healthy and up to speed. Bringing in someone new just means they have to start learning the system from scratch.
At this point, unless they have serious injuries, they should only be looking to trade for big men, if they can get a real upgrade (like a Smith or Varajao type), not just another end of the rotation player. Otherwise, work on getting the guys you have up to speed.