Is a model release needed if a model posed for a shooting but isn’t identifiable?

I’ve seen variants of this question but couldn’t find my specific case. So what if I have someone specifically pose for a picture but in the end product they are not identifiable by any means.

Do I need their consent or even a model release if I:

  • want to upload the picture to my portfolio
  • want to exhibit the picture somewhere
  • want to sell the picture

Also if they someday decide they don’t want the picture to be seen by anyone. Can they make such demands if they can prove they posed for the picture even if they are not recognizable on the picture in question?