First off, I'm not a lawyer, I'm not your lawyer, none of this is legal advice. Go get legal advice from a lawyer.
A lot of us know by now a little about how Mickey Mouse being in the public domain (at least in the U.S.) works. You can use the version of Mickey from the animations (Steamboat Willie and Plane Crazy) that entered the public domain this year because they were released in 1928. So long as you:
- Don't use them in ways that would make it seem that your work was made by Disney and
- Don't use any elements of Mickey from later works which are still under copyright.
So no Donald Duck. No Goofy. No gloves. You can't make his pants red. Etc. Right?
However, let me present a few movie posters from 1928 which are now in the public domain:
Yellow gloves! Red pants with both yellow and white buttons! Yellow and brown shoes! And a green hat to boot!
I'd imagine all of these posters qualify as creative works that would have gained copyright protections as soon as they were made/published. And the copyright on these poster illustrations have all now expired, leaving these posters in the public domain. (Copyright-wise, at least. Trademark is a whole other kettle of worms.)
So, theoretically, all the elements you see in those posters should be fair game today. Which leads me to believe that theoretically there's no reason why people who use the public domain version of Mickey Mouse in their own works ought to avoid red pants with yellow buttons or yellow shoes. Yellow gloves are probably similar, but the case for white gloves being safe to use is probably weaker given that the only images I could find from 1928 where Mickey's wearing white gloves are black and white illustrations.
I say "theoretically" because of course law is complex and (again) I'm not a lawyer and who knows what legal arguments Disney's legal department could come up with. But I don't see any reason off the top of my head why using red-pants, yellow-shoes, yellow-gloves Mickey in your own works (so long as you don't include other elements that legitimately didn't become a thing until 1929 or later and didn't infringe on Disney's trademarks) wouldn't be virtually just as safe as avoiding colors when using the Mickey Mouse character.
All that said, I'm definitely open to being set straight on this. I just hoped to get a little discussion going about this.