I guess I'm just dense - I can't figure out what it is that you're trying to do. I went into Settings->Sound->Notification sound and all of her ringtones show up in that list.
Then, I used ES File Explorer to copy a random file from /sdcard/media/audio/ringtones into /sdcard/media/audio/notifications and it pasted just fine, so that directory isn't read-only.
Perhaps if you just say what you're trying to accomplish rather than worrying about files and directories it might be easier to help you?
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