Aurora is probably the classic Walt era princess with the least agency. The only agency she seems to have is in trying to get her aunts to let her go with the man she loves, but even that gets squashed when she thinks she has to be betrothed to another guy.
Snow White actually has a lot of agency. She runs away from the evil Queen who is trying to kill her (even though she was told to do so), she asks animals where to stay and finds said place, and she thinks of ways for the people who own the home she found to let her stay. It is only in being so naive she gets poisoned that she is really bad in any way, I would say. Snow White is supposed to be 14, still a child, so of course she acts so mentally young in the original animated feature.
Cinderella has a lot of agency as well, and rivals Snow White, if Cinderella is not better. She pushes her stepmother to let her go to the ball, and works hard for it and tries to make her dress for it. When that gets sabotaged, yes, she must rely on a fairy godmother, prince, and animals, but she cleverly thinks of how to get the cat away so the animals can free her, and of using the other slipper to prove her identity and secure her happy ending.
Still, Snow White is the best of Walt's classic princess films. It has the most emotion. I feel bad and sad when Snow White, the innocent, gets poisoned. I feel so sad when the Dwarfs mourn her. And I feel so much joy when Snow White practically wakes from the dead and lives happily ever after.
Cinderella has near that much emotion, but not quite. And I would say Sleeping Beauty has less emotion than Snow White or Cinderella. Yes, I identify with the critics who find it distant and cold. Sure, Sleeping Beauty is the most beautiful of the films, but that's style over substance I say.
By the way, Sleeping Beauty was not quite a bomb. It was the most popular film after Ben-Hur of the year the films came out. Sleeping Beauty was just so expensive it couldn't make all its money back that year.
And yes, it's amazing Snow White still holds up all these years later. The fairest one of all. Certainly will remain fairer than this remake.