Finding (Someone's) Art of Disney's Fantasia

This past week marked the anniversary of the debut in 1940 of Walt Disney's classic film Fantasia.  Remembering this reminds me of the two pieces of someone's original artwork I found at a Southern California estate sale.  The two pictures were tucked inside an original 1937 copy of the program for the premiere of Disney's Snow White and the Seven Dwarfs.

The two pieces of art show characters from the "Pastoral Symphony" section of Fantasia. And I have no idea who drew them.

Zeus and a Centaurette, who were stored inside the 1937 Snow White premiere program
when I liberated them from an estate sale earlier this year.

An artist friend told me that these two pieces look like "fan art" to her -- they don't seem to have the quality that a piece of concept art from the Disney Studios would have had.  

And yet the pieces of paper have holes punched at the bottom that seem similar to pieces of original Disney concept artwork I've seen online.  As well, the drawings don't exactly resemble the finished versions of the characters in the film, as much "fan" art would.  

The first sketch is mounted on black paper, about 8 x 8 inches, and it shows Zeus tossing a lightning bolt down from heaven.  

The Centaurette, about 10 x 11.5 inches, is on cream/white paper, blond with blue eyes.  And, as you no doubt immediately noticed, she's slightly more anatomically-correct than the Centaurettes in the film.  

The signature on the lower right seems to say "P. Bear" or something like that.

I have read that Disney employed many concept artists, who made drawings based on the ideas tossed out as animated features were being developed.  Their drawings don't always look much like the finished characters in the film. 

The only other clue in this mystery is the fact that a lot of the members of the audience at the premiere of Snow White and the Seven Dwarfs in 1937, were Disney employees.  

Did one of them smuggle home some original concept art for Fantasia (which was released in 1940) and store it inside their rare copy of the Snow White program?
  
I realize that I may never know who drew these pictures.  Meanwhile, I welcome input from Disney historians on the subject.
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Here's my previous blog post on the Snow White premiere program: http://estatesalechronicles.blogspot.com/2014/09/opening-night-program-for-disneys-snow.html