Re: Aurora and her human tree...
Am I potentially reinforcing bad biting behavior with the way that I am scolding when she nips, then changing to a happy tone when she stops??
That is a real possibility. What I think is happening, is that Aurora is becoming very territorial about her cage and is trying to protect it against those invading fingers. Some birds tolerate fingers in the cage, others don't. A territorial or nesty bird definitely will not, and you risk being bitten hard whenever you do it.
She's doing what is natural for her by biting the cage invader. It's probably going to be best for you to modify your behavior, than to try to train her to modify hers. It will also be safer for your fingers.
It sounds like she is doing well on you and away from her cage, so do that when you can. You will both enjoy it much more.
Barb
Happiness is a firm banana