I found 4 of them but have only had to use 1 to make it to the final battle at the moon temple, what are the others for? Am I missing some statue people? Can they be used down in the crystal forest undergeound?

Try starting over and use 1 Supersoft on the petrified soldier blocking the path then return and get the other four for something else... hee hee. When you collect all 4 and expend 1, they all disappear like they magically spilled all over the ground.