

Fanfiction and non monetised use is not at all exempt from these laws but rather tolerated by the copyright holder.
Should fix that in law, based on the commonality of such use.
IP companies use every such opening, we should too.
combination of plausible deniability (wizard uk boarding school isnt that orginal)
Except they even use character names from HP.
Publicity - maybe, would be funny.
Perhaps now - yes. 20 years ago one could argue, but today in practice it, as it was intended, simply already doesn’t exist. Those holding the IP are those having enough power to insert themselves in a right place. The initial purpose is just not achievable.
Yes, if the artist thinks that. And no, if the artist expects to make some money from every copy.
That’s true for patents and technologies, but not true for art and software, where it’s improbable to just come up with the same thing.
Now - maybe. There are a few traditional ways, like authors reading aloud pieces of their creations and people buying tickets to such performances, same with music. And models with paying forward for a request, like crowdfunding or an order.
But personally I still think some form of it should exist. Maybe non-transferable to companies and other people other than via inheritance. Intellectual work is work, and people do it to get paid. It’s just not good enough if the returns don’t scale with popularity.