Ignoring that the mouse looks a bit like Mickey (more like Mighty Mouse IMO), they are opening marketing the book with dozens of trademarked MCU and DC characters on it. I can't imagine either company allowing any of them on the cover these days.
Yeah, not without advance permission, anyway.
The mouse in question on both Adams covers is ATOMIC MOUSE, published by Charleton from 1953-1963.
I didn't know till you mentioned him that Mighty Mouse was a publication of Timely/Marvel beginning in 1946. Although it began as a Terry-Toon animated cartoon character, apparently licensed to many other publishers over the last 7 decades.
In less litiginous times, Disney tolerated them, both the Mighty and Atomic mice, without a problem.
