budgies
You can keep myna birds, parrots, canary, finches, caiques, and quite a few others.
Indoors. They adapt quickly.
Yes, many small animal pet owners keep their animals indoors, this is perfectly fine.
To prevent cats from catching birds, keep your cat indoors or supervise outdoor play. Consider using catios or outdoor enclosures to allow your cat outside safely. Additionally, using bells on your cat's collar can help alert birds of their presence.
Unless you provide a special environment for it, it will die indoors.
He's afraid of birds that come indoors so yes
Keep it warm apparently the leaves fall off even if you keep it indoors, so there's no need for light
Add freon
This would depend upon the zoo, but I think for the most part the answer is no. Most zoos that I have seen either keep their bird displays indoors or they have a large overhead net to keep the birds from flying out. Clipping a bird's feathers prevents him from flying, which is not healthful to the bird. For pet birds, this can be tolerated if needed because they don't need to fly much anyway, but even then it's still better to let them have their feathers and be able to fly.
Birds are covered in feathers
So the animals don't murder them in their sleep.
It is ideal to keep a cat indoors for at least nine or ten weeks. It is recommended by taking the cat out on a harness for the first few weeks after the indoor period, to get it accustomed to the yard or garden.