I'm perfectly happy for some Dolls to have a natural edge over Yazuko - anyone going up against Sickle-Cell with a bladed instrument is going to have an interesting time, so things could always be worse :P

As far as Melody goes, it seems as though she would be experiencing a [i]lot[/i] of hostile intention once she flips, even if it's fixed enough to stop Yazuko from picking up her normal cues about when someone intends to pull the trigger on her (since she's constantly in the same headspace). Certainly impossible to override using her projected emotions, but I'm open to discussion as to whether or not she'd be visible on her emotional radar. Even if she effectively became invisible to her radar once she flips, I'd be content with simply triggering that state at particularly awkward moments and dealing with the consequences :P How much target prioritisation does Melody retain when she triggers?

Also, interesting thought - if Yazuko can trigger Melody by bombarding her with fear and paranoia, how much would she be able to hold back Melody's transformation by dropping a dumpster's worth of peace and serenity on her head? It doesn't override the underlying emotions (so I doubt that she could simply keep her out of that state indefinitely), but how would things work if she didn't feel that either of them were in danger? It's all somewhat hypothetical, since she would still use her swords on Puppeteers regardless, but I could imagine circumstances where it would be relevant. On the same line of thought, does she simply return back to her normal state once there's no longer anyone else around to perceive as a threat, or are there more intricate cues that that?