Not sure about the drummer, but the halbred and banner guys have q thin strip of cloak that is part of the arm. Turns out is not a big deal, you can easy fill in the connection or just leave it really.
The Torso is split in two, and the from "clips" that go over the shoulder pads are part of the front half. You could trip the back half of the torso and an Eldar front torso to match, then just greenstuff up some clips.
Not a big deal for me, I'm using them as the base for some exodite fire dragons.