I think it's fine to post about this. Will did a FB live video this morning talking about this very issue. He has a characteristically calm and reasonable response to the change in the project status.
As for your question about making/selling fan art: There is clearly a market for fan art out there. But it is important to understand what you are doing when you make fan art and even more importantly when you try to monetize it.
Whether you are making money or not -- the mere act of creating fan art is a copyright infringement. The important bit is whether the fundamental infringement rises to the level of an "actionable" infringement.
I was drawing comic characters from the age of 8 when I got my first X-men comic from a friend at school. While all those drawings were "technically" infringements they never rose to the level of "actionable infringements". Along the way I got more invested in the Marvel characters, I became a little "cooler" to my friends at school, and I learned how to draw.
So yes -- I think that fan art can be a useful and productive thing.
It's when you try to monetize fan art that you need to go in with eyes wide open. Understanding that the fan art you make is fundamentally an infringement. You are creating copies and derivatives of intellectual property created and owned by someone else. If you are going to use and generate income off fan art, without negotiating a license beforehand with the Intellectual Property (IP) owner, you need to have a full and complete understanding of the Fair Use Defense. And in the case of some characters, you need to understand Trademark Law.
Which goes to the second half of your question -- is it worth the risk trying to sell it?
I have made concerted effort to study copyright law and how it pertains to illustrators. In the absence of a license from the original IP holder I have landed on -- No -- it is not worth trying to sell it.
It is, in my opinion, always better to negotiate a license with the IP holder if I want to sell fan art.
And I want to clarify -- the term "negotiate" can vary in it's meaning. Most people think it means "pay" (and often it does) but it can also just mean "ask and get permission".