Wouldn't it be funny if Hades sent Deirdre as his representative?
My first thought was that it was an amusing idea that made no sense. But then as I thought about it it struck me that in a lot of ways it
does make sense!
Assuming Hades wanted to send a proxy, I don't know if he would be allowed to use a shade, either by cosmic rules or Accords rules. I'm also not sure how much control he would have over her shade once she was outside his demesne.
But if he can do it, and control her as he does, from his POV sending Deirdre actually would achieve several things. For ex, it might be part of her punishment, being able to perceive and even move within the mortal world, but unable to sample its pleasures or enjoy it. If Nicodemus is somewhere around (which would not surprise me in any way), letting father and daughter meet again, but forbidden any communication, might serve as both additional punishment for Deirdre and payback for Nicodemus, too.
Her presence might also be a useful 'don't cross me' reminder to others who have forgotten how dangerous that is, too.
It could actually make sense.