Elke I love your idea of the coccoon transforming into a butterfly. As for

, here goes... Bear with me...
There is someone in a butterfly costume. It starts off just as a coccoon... maybe they can be unravelled or something, and wings sprout from beneath the coccoon layer. This isn't on fire, but just normal so that people get the symbolism. They do however, have a single flame in the hand for the firey part, which comes next.... For the firey part then, you could have several coccoons with the wishes divided up between them. One person surrounds each coccoon - these creatures are kind of curled up on the ground. They have fire fans or something like wings. The person in the butterly costume runs around to each coccoon in turn and lights them. The people folded next to these coccoons (with their fans/wings over them or on each side of the coccoon), light their fans from the flaming cocoons and proceed to dance around the big main colourful butterfly like little firey butterflies. It gives a kind of "wake my children" feel to it too, so still quite spring goddessy-like

Did that all make sense?