Welcome to you and Kiwi!
Kiwi may stop plucking with patience, attention and proper feeding. My Chica was quite badly plucked in areas when I got her from an abusive home but she stopped plucking almost the instant she came to me. She had lived with poor diet, no attention, no toys and just total neglect for three years. Also, the prior owners were crack cocaine users who smoked it in the same room and I think she could have been addicted from the fumes as she screamed constantly for the first week. I found she calmed down when she was cuddled and received head scratchies. I don't know whether this will hold true for other QP's or other birds as this was my first experience with any bird and I only took her in until I could find her a good home -- three years ago.
I went to my local bird store and got a copy of Mattie Sue Athan's book, Guide to the Quaker Parrot, and read everything I could find on this web site. Then I set out to gradually rehabilitate her and now she is the sweetest, most loving, happiest pet I could imagine. Maybe my experiences will be helpful to you -- I hope.
Bless you for taking Kiwi into your heart.
Lizz and Chica the wonder bird