The traitor need be someone who have been on Egghead for the last two months, is able to control the Dome and Sea Beasts and have control on the same lvl or above the Vegapunks over the Seraphin. It must be a Vegapunk
We can assume at least Shaka isnt involved, as there's no reason for he to panic when he was alone looking at the cameras if he was a traitor.
Liilith, York and probably Pythagoras are turned into stone, what can be undone.
Atlas was destroyed when the Dome was closed, but know is ok
Edison is destroyed but can be easly restored.
I really like the ideia of all those 5 Vegapunks being traitors. But If they are all traitors, why they would be doing some things like being turned into stone, sending S-Snake to attack Pythagoras, sending S-Bear and Hawk to kill CP0, they could just use the Seraphin to kill the SH and CP0 without hiding themself if they are all traitors.
Think at the end will be only one of them, and by now everything points to Edison, even If It seems kind random, and pehaps he já working with the WG.