tbh copyright rules are pretty strict, but not a lot of people actually follow them. i'm not a lawyer or anything, but a while ago i was looking into something similar to this a while ago.apparently even creating fan art can be considered "illegal" as it's intellectual property. more creators won't pursue legal action mostly because it's more trouble than it's worth. it's like a free promo to the creator. it gets very tricky when you start selling things for a profit though.
no idea if this helped at all, but uh