Can I dye a pumpkin?
Well, yes you can... lots of people dip dye pumpkins using food coloring, though the outer skin of the pumpkin will not absorb the dyes as well as the flesh of the pumpkin. If you want to enhance the dye absorption on the surface, a very light sanding with a fine-grained sandpaper to lightly score the surface will probably help there. As you have the small ones to test, I'd test both scored and not to see how it works out.