The team over at Minion City made these animatronic pumpkins with their own Minion dev board, but you could also use a wireless radio board. For each pumpkin, they used a battery pack, servos, and a small perfboard, with GE Color Effects for the lighting.
After carving out faces, they hot glued a servo inside each pumpkin and attached piece of a wire hanger to open and close the mouths. Then, they made 5V regulators and connectors for the servos and lights using the perfboards. Finally, they attached a battery pack to each one. You can see more of the setup in the video below.
Visit the project page to learn how to program the pumpkins and light effects. Check out the videos below to see what else they can sing.