Grown wings can be enough to lift a person, sure! They likely won't be able to use them for any long-term, cross-country flying, but a character with wings could get off the ground and fly around for short periods of time, sure!

Pseudo-legendaries are fine! We're only restricting outright Legendaries, for obvious reasons.

The transformation can be painful if you'd like it to be, or you're welcome to simply wake up with it one day! The choice is up to you.