I understand that bravery can be defined in different ways. All of them could be considered brave. Some of them have more scary/action scenes in the movies than others.

^I agree, there are different types of bravery. All the young heroines are brave in their own way :)
I think Lilo is very brave because she has been through so much, especially at such a young age, and still pulls through. I think Melody is also brave for going to the party, for following her dream and defeating Morgana.
If I had to choose, I would pick Jane - she has gone through so much in her life (with WW2 for goodness sake!) and also defeats Hook.

She had to live during World War 2 for goodness sake

Oh, for Goodness Sake!

A lot of them are brave, but Vanellope was brave enough to stay behind to die when the Cy-Bugs were attacking.

I think she was very brave to stand up to the Queen of Hearts