Speaking of the “humans in animal suits,” “animals heads on human bodies,” and “humans with animal traits” levels, I understand why Maus is the way it is. The characters in Maus are actually human characters and have very anthropomorphic animal shapes to the viewer. Maus appears to be “animal heads on human bodies,” but the character’s animal shapes are metaphorical, making it easier to suspend disbelief toward the treatment of them as human characters.
The Mickey and Friends verses (like the Mouse comics and the Duck comics) goes the “humans with animal forms” route with its more anthropomorphic (“Animals with Many Human Traits” appearance-wise) animals like Mickey Mouse, Minnie Mouse, Donald Duck, Daisy Duck, Huey, Dewey and Louie, Scrooge McDuck, and Ludwig von Drake. However, unlike Maus, the animal forms are literal, they are half dressed (shirtless mice and pantsless ducks), and what kind of human sounds quacky in a typical natural voice. This makes it harder to see them as basically humans who just happen to be done with animal forms.
It’s easier to see Goofy, Max, the Beagle Boys, Duckworth (he’s not a duck), and their ilk (Dogfaces), as well as Pete and PJ in Goof Troop, A Goofy Movie, and An Extremely Goofy Movie, as being basically “humans with animal forms” because even though their animal forms are still literal, they are more anthropomorphic, either “humans in animal suits,” “animals heads on human bodies,” or “humans with animal traits” (like Roxanne in A Goofy Movie) in appearance. They also dress as fully as any human – shirt, pants, shoes, and all.
Also, there are some less anthropomorphic animals (Milton the cat, Chip n’ Dale, Humphrey Bear, And Louie the mountain lion) and slightly anthropomorphic animals (Pluto, Dinah the Dachshund, Butch the Bulldog, Fifi the Peke, Chainsaw, Figaro, Mr. Pettibone, and Waffles) who are portrayed either as “normal animals” or “animals with human traits.” This, along with making the “normal animals” pets to the anthropomorphic animals (Mickey has Pluto, Goofy has Mr. Pettibone and Waffles, Pete and Peg have Chainsaw, and Minnie has Fifi and Figaro), only makes these universes rife with Furry Confusion.