(Additionally: I know the watermelon has horns because "Suika" can also be written as 西瓜/watermelon, but ...do the strange faces on the lemon and pepper have any significance?)
Delta_Wave said: Green-pepper : go google-image search with スプー , and is a charactor in ぐ〜チョコランタン(goo-choko-lantern), a TV show program for little kids.