Are all play sets compatible with each other? Can they all be connected? Are all the tracks interchangeable? Can a Smart Friend character interact with GO! GO! Smart Wheels and/or Animals? Can all cars for Go! Go! Smart Wheels be used on any Go! Go! Smart Wheels Playset? Is there a disclaimer on manual that Go! Go! Smart Friends is the only playset with MagicPoints? What is the difference between Smart Animals, Wheels and Friends?