Frankly, I believe getting into debates as to whether the cat leak is real or not is rather pointless now. VGAs aren't that far away from now, and if for whatever reason, there's not any Smash announcement, worst case scenario, it'll come not too long later, since Nintendo is on borrowed time as they're legally obligated to have all characters released before February 2020 ends (92 days to be more exact).
Now, history can repeat itself as much as it can't. This year has shown us too well that DLC characters aren't immune to leaks as many people thought a year ago when Joker was revealed.