Mickey mouse is in the public domain, at last!

I think they would have a very strong case that using the mouse on a product is likely to confuse consumers about the origin of the product and therefore infringe on their trademark.

Nah, Disney seems to be genuinely letting it go. Amazon and other sites are flooded with Steamboat Willie merchandise at this point.

In fact I play cornhole competitively, and last year I picked up a set of Steamboat Willie themed bags:

https://www.logiccornhole.com/products/steamboat-willie-colo...

If you go to the homepage (or look at the banner) the project is shut down since 2015.

https://fffff.at/rip/