I think Xander does still have vague memories, but I can't see him willing to shoot someone from a distance without trying to talk to them--reason with them. If nothing else, I think he'd insist on looking someone in the eye just because he'd see that as the moral thing to do.

And I think Spike, just like in canon, is completely deluded. He thinks this is one more game and that she'll come back to him the second she needs a good fuck.