おせっかいかもしれませんが一応。
removeしてappendせずに属性を書き換えてあげた方がすっきりするかもしれません。

Before
<remove xpath="/Sounds/SoundDataNode[@name='trader_jenlikequestaccepted']/AudioClip">
</remove>
<append xpath="/Sounds/SoundDataNode[@name='trader_jenlikequestaccepted']">
<AudioClip ClipName="#@modfolder:Resources/Sounds.unity3d?yorosiku"/>
</append>

After
<setattribute xpath="/Sounds/SoundDataNode[@name='trader_jenlikequestaccepted']/AudioClip" name="ClipName">#@modfolder:Resources/Sounds.unity3d?yorosiku</setattribute>