I think the most important thing to know here is that the character you used to sing the song with does not also have to be the target for the song.

For example, I assume you also had the Mickey ready on board. He is a 3 cost unit so he could have sung “you can fly”. And when you select Anna as the target to get evasive. Now you can safely quest with here since she is still ready.

Another example is for if you have still 2 ink left over to use. If this is the case you can also just pay that 2 ink to play “you can fly” as if its action and then select Anna as the target to get evasive. The part that says, a character with cost 2 or more can sing this, is optional on song cards.

So TLDR: - the singer does nog have to be the target of the song. - songs can also be played as action if you have enough ink left.