Those questions are all interesting in themselves, but utterly irrelevant here.
The first one asks if someone else than the „prompter“ should have copyright.
The second one asks about other people‘s copyright.
The third one is answered by case law, including the Monkey Selfie case. The wildlife photography setup is very much comparable to your typewriter there.
If there's a thousand monkeys with a thousand typewriters, and they all write a single page to a thousand-page epic, is the scientist allowed to copyright and sell it as a book?
The first one asks if someone else than the „prompter“ should have copyright.
The second one asks about other people‘s copyright.
The third one is answered by case law, including the Monkey Selfie case. The wildlife photography setup is very much comparable to your typewriter there.