>> So someone could publish a version of 1984 that had certain characters completely expunged from the text, and others added.
No real need to publish anything, we're living a variant of it every day. Without much creativity, we could map so many day-to-day things in 2020 to items in 1984.
Are we? Where do we find characters like Mustapha Mond? Instead we got the likes of Bezos, Musk and Zuckerberg. No opinion about David Shaw and Jim Simons.
I've seen this a few times. I'll say what I said last time:
If many people are substantially harmed by wasting their time and energy on distractions, then those who waste less time will outcompete them. Whether the mechanism is common wisdom analogous to "don't drink alone or before the evening", parents teaching their kids in certain ways, religions that consider much "wasteful" entertainment to be sinful, or genes that contribute to conditions perhaps resembling autism where colorful flashy video registers as annoying or even painful, the problem seems likely to create its own solutions.
One of the premises of "Brave New World" is that all children are raised by the State, and are forcibly (a) oxygen-deprived in the womb to limit their intelligence and (b) subjected throughout childhood to indoctrination and hypnotherapy to make them say "I'm happy and content with my life, and my only desire is to chase consumer goods". I'm not sure why so many people seem to forget this.
> I'm happy and content with my life, and my only desire is to chase consumer goods
Seems a pretty good summary of the whole wellness/"gratitude"/mindfulness culture that now exists and seems to think that an epidemic of mental ill-health can be fixed through breathing exercises and meditation apps for one's smartphone.
Orwell reviewed That Hideous Strength and said it had some good points. But it's definitely the weakest in the trilogy, and definitely did not influence 1984 in any obvious way. Still worth reading, though.
He may be talking about the underrated Swastika Nights. A new world, after memory of the old one has been erased is part of the plot, as is a secret manuscript.
That said, stories and plots have been retold ever since the beginning of literature. Here's a lovely article about various versions of the well-known story about the Baalshem being asked to intercede for a sick child: https://brill.com/view/journals/jjtp/22/2/article-p127_2.xml