You can add some natural yogurt to his diet to provide some good flora for his digestion. Keep him warm is the most basic advice, if you have a desk type lamp you can turn to shine on him that will suffice. I just private messaged you a link that may help advise you.
I don't always put the corner cage in a corner, the cages get moved around often. I find that one of the flat sides does just fine against a wall. Right now our Elanora Too is in the corner cage it is his favorite, sometimes Pookie tries to take it over, that girl has Grey issues of domination.
When I read your entry it sounds like you are rewarding her bitey behavior by giving her attention. I would ignore her and cage her when she gets antisocial then release her after a few minutes and repeat as needed.
The birds that live here all shred paper and cardboard all year round. I think he is just keeping busy while you are "working" at your desk he may feel like he is doing the same.
Another step forward and I know those steps are sometimes just leaps of faith. My heart is with you and next weekend is going to be even colder, Brrrr.
Sometimes running the vacuum cleaner gets my birds bathing in their water bowls. When you mist do so over them not at them so it falls gently over the bird.
The more we love them and the more difficult the struggle whether for health like Ollie or aggressive personalities it seems those birds, cats, dogs and people leave the biggest holes in our hearts. Sending love and wing hugs. I know Koko will share some love.
Excited to hear you have taken a grey rescue into your home and looking forward to the continuing saga of Captain Jack. Sounds like you are starting out right, going slowly and not asking too much of him until he lets you know he is ready. Scoring points by making foraging opportunities for him as well. I think you should have a successful relationship with the Captain.
I love my corner cage just tricky getting the paper folded to fit the bottom tray. Big is good that means she has room to get some exercise when inside.
I think the raw mushrooms might be a problem as the spores are so fine and can be inhaled. I know I have read studies and they eat some Fungi in the wild.
As odd as it sounds there is a hybrid between a Roseate Cockatoo and a Cockatiel in Australia back in 2006 if I remember correctly. Surely a Grey/other Grey cross might be possible not trying to advocate for one just thinking what might be possible.