Okay so here's why I think it's Wes.

Here's reason one

When Matthias asked Double X if he knew the absolate (can't spell for crap sometimes ). Double X responded and I quote "intimately" 

 Here's the definition of that word in my own wording "closely" . Okay let's out it this way if you know someone intimately that means you're really close and know that person well. And who knows it and worked on it? 

That's right WES!

Here's reason two

Double X 's signifies dying/some who's dead. Like the outline of the body and X's where drawn on the eyes signifying the died.

Here's reason three

People can survive a shot to the head and can live with the bullet there. Deb used a blank so there's a strong possibility that he still could be alive

Here's reason four and it ties in with the second one.

So Wes is supposed to be dead right? But if he did survived it makes sense why his eyes on the mask have double x's.

Also anyone else think of Wrench when you see Double X? His mask just reminds me of Wrench's mask. If you don't know who that is look up Wrench Watchdogs 2.