Interesting - so whether LW is a separate ballad depends on how much importance you give to content (sister + incest vs brother) as opposed to form.

Perhaps I should take this to the other thread, but I'm not sure how much weight should be given to the unstaunchable wound as a distinctive feature of Twa Brothers - there was a folk belief that a murderer could never staunch the wound [s]he'd inflicted, to the point where the touch of the murderer's hand was supposed to open up wounds that had closed (as in Young Hunting).