Not that I think you care, I'm just using your post to share. The title "adversary (satan)" in Judaism applies to an entire "encampment" of angels. There's the head angel who is in charge of testing mankind in general and smaller fractals in charge of individual people with the various inclinations we have. It's not two different satans, it just that it depends on whether you're talking about a general or individual level.
With regard to angels, although it is true that angels are an extension of G-d's Will (actuall an extension of an extension, not a direct extension), there exists an argument among Jewish scholars whether angels technically have free-will. By technically I mean, that even the side that posits they do have free-will, the Truth of G-d's domination is so apparent to them, that going against what G-d wants would be as crazy to them as jumping into a fire, but the option does exist.
It should also be noted though, that Jewish texts describe humans as being "extensions" of angels in a similar manner to angels being an extension of G-d's will. The question of angels free will seems to be related to whether there exists any degree of "not G-d" within the dimension of the being. In our dimension, its the majority and therein lies out ability to choose to follow G-d or not G-d. On the angelic dimension, it's the minority, but present nonetheless (perhaps in the existence of the extension of G-d's will appearing to manifest in the angel itself which is something that is not-G-d Himself, but I haven't yet seen it explained) and perhaps that degree is enough to grant them the potential ability of free-choice.