Yeah, I think you can totally read it as Dream fucking with the cat. But honestly, I get the feeling Dream would be just as fine being a feline-morphic representation for cats as an anthropomorphic representation for humans. Desire, Despair, and Delirium would probably be pissed though--what is desire going to do with a heat cycle? Delirium would be limited to catnip binges. Which might honestly be enough incentive for Dream to make the cats flip the universe. He's capricious like that.