The traitor thing was so easy to figure out. In addition, I'm surprised that no one figured it out yet.
Now even though it appears that the traitor is Sally. But that would be stupid because at the moment, Sally is robotized (at the cost of saving the world btw). Now what I think is the case is this:
Remember, the main point in this is that someone from the ORIGINAL Freedom Fighters betrayed the team. This happened already. The original freedom fighters are not the group of Sonic, Sally, Antoine, and Rotor (that one is considered to be the most popular & arguably the most legendary one). The original freedom fighters consisted of Colonel Tig Stripe (leader), Sir s, Spot Long, MP Bull Bones, and Trey Scales. Trey was actually the traitor of the group (how ironic that he was really a snake) which lead to the original freedom fighters to be deceased. Not to mention that the second Freedom Fighters (which was influenced & looked up to the original freedom fighters by Sonic & Sally), are no more as well. So the fact that Silver is looking for the traitor is irrelevant at this point.
There was a issue where Harvey who crosses off names of who isn't the traitor and Sally is one of them.
there is an easier answer so, im just going to leave this(below) to help speak for me.
SatAM/Archie Characters in the Games - Petition! Sonic: "Really? Other me's??!?!" >>> sbemail150 >>> Sonicparidox-UniverseMap Sally: Oh Amy, Silver and I got a surprise for you(careful with the armband thingys). Amy: Umm.. Sally? Who are the two--?? Sally: They are our half-sister daughters! Amy: WHAT!!