So what's the basis of the lawsuit against Disney? There's no damages, so equitable relief? Of what?
You probably guessed correctly: equitable relief in the form of an injunction against Disney bringing a trademark lawsuit. I haven't read the complaint, but I'd be surprised if it didn't cite Kellogg and Dastar.
The Supreme Court of the United States has decided a few cases about the interaction between the Lanham Act, which inclues trademark law, and exclusive rights pursuant to the Copyright Clause. Key cases includes Kellogg Co. v. National Biscuit Co., 305 U.S. 111 (1938), and Dastar Corp. v. Twentieth Century Fox Film Corp., 539 U.S. 23 (2003). In both cases, the Court ruled that the Lanham Act cannot be used to extend the effective term of exclusive rights in an invention whose patent has expired or a work whose copyright has expired. Disney's legal counsel ought to be familiar with the latter case, seeing as it involved a company that is now a subsidiary of Disney.