My grandma had a parakeet. So I won't be able to answer a lot of your questions. But I love the "on a scale" question - it made me
a little bit - even though I can't answer it.
If you wore a thick glove you could put your hand in the cage and it would hop from it's perch to your hand. You had to wear the glove because it would bite your hand first. Then you could pet it with your other (ungloved) hand - it would only bite the hand it was sitting on.
She would let it fly around and she just leave the door to the cage open and it would return at some point (probably for food).
It was noisy-ish a lot of the time but if you put the cover over the top of the cage it would be quite or go to sleep. But of course you wouln't want to do that all day.