1. After crossing the lake with the springs and the ramps, you will come to the point where you first find the Spheres that can breathe fire. Use a homing attack on the first one, and you will see it in the air. I'm not sure how to get it, but try homing attacking in the air.
2. It's in your path in the building with the fire torches. Jump through the pearl circle, and you'll get it.
3. After doing the sidle part of the level, you will have to cross another lake that has a few rails on it that lead to the road to the castle. When you get to the rails, take the middle one that's on lower ground. You will hit a spring that will launch you to the soul.