In the comis, the Silencer still has her visor; it depends on the artists. Then again, considering what her nanode is capable off, I guess she can have two settings for her costume.
Concerning the Dreadfuls, they all come from one of the parallel Earth already explored (the one with the Vampire Justice League, the Metallic and the one with gender swapped heroes, I suspect). But I'm willing to bet that they are new characters.
And yeah this cover is glorious.