Dear KStirling,
Thank you for starting this new post. I have been always wondering who made these beautiful illustrations. However, I have never got a response. In my opinion, JAQ is very right. These two plates were surely made for the film.
Leaving the authorship aside, I think this is the best representation of the character ever made. The artist really captured the devil in Peter Pan. In fact, I think that David Wyatt may have taken some inspiration from it for his cover of Peter Pan in Scarlet.