One thing that a lot of people don’t know is that all uplifted cats are descended from the Hemingway Cats.  They were considered the smartest and most adaptable of their kind, and the original gengineers spliced a lot of other cat species into them as well.  The final result was on the large size for a standard housecat, but still within the range of possibility.  The main two differences are the extra toes and opposable thumbs.  And of course their minds.