Sorry, Thrilla, but I think I know Kirby's properties far too well to call this MU even. Our utilt outranges a lot of Fox's attacks (and clanks with his smashes while having faster start-up time, meaning that buffering another utilt after a clank means Fox will get hit), and it's not hard AT ALL to hit any character with utilt (even MK and Snake). Our ftilt can knock Fox in a horizontal position at any % and combo from bair (bair>ftilt) giving us an easy ~20% at any time before high %s, and we can also angle it up to hit them from a diagonal range (and it being disjointed, at some points it can knock Fox out of his dair). We can also bair Fox out of his dair, and Fox takes more damage than we do when we trade hits, so it's a MUST if the Fox's patterns are easy to read... And our fsmash destroys Fox's aerial approaches, no matter which he chooses (as long as he's in range, which is no problem at all for a disjointed moving hitbox like Kirby's that kills early, and can be angled upwards to cover more aerial distance).
Kirby really doesn't have to approach once he's got an advantage, which Kirby can get easier than Fox. Fox HAS to rely on slow damage-racking options since we're lightweight and can get out of combos super easy (Kirby can still get out of the dair>utilt after ~10% if we are in front of him, and since he'll be aiming his dairs to be landing behind us, it won't be hard at all), plus us being a small target we can SDI out of a lot of stuff easier than other characters whose hurtbox take forever to get out of an attacks' range... While we hit Fox with ont utilt/dtilt/pummel/grab and he's well on his way to a large amount of damage in a single sitting (if Fox somehow SDI's out of fthrow>uair, it's got to be at the third fthrow since his fastfalling properties make it impossible for him to get out of our grab range while we do the combo, since we DI towards him while uairing which resets the spacing Fox creates).
We can make many more mistakes than what Fox is allowed to do... One mistake from Fox and he's hurting baaad, or dead at ~100% from a fresh up-angled fsmash (just like our mistakes may cost us a stock from a fresh usmash of yours)... But we have an easier time taking you up to that ~100% mark than what you have taking US to the ~80-90% mark.
I don't think this should be called even.
Kirby really doesn't have to approach once he's got an advantage, which Kirby can get easier than Fox. Fox HAS to rely on slow damage-racking options since we're lightweight and can get out of combos super easy (Kirby can still get out of the dair>utilt after ~10% if we are in front of him, and since he'll be aiming his dairs to be landing behind us, it won't be hard at all), plus us being a small target we can SDI out of a lot of stuff easier than other characters whose hurtbox take forever to get out of an attacks' range... While we hit Fox with ont utilt/dtilt/pummel/grab and he's well on his way to a large amount of damage in a single sitting (if Fox somehow SDI's out of fthrow>uair, it's got to be at the third fthrow since his fastfalling properties make it impossible for him to get out of our grab range while we do the combo, since we DI towards him while uairing which resets the spacing Fox creates).
We can make many more mistakes than what Fox is allowed to do... One mistake from Fox and he's hurting baaad, or dead at ~100% from a fresh up-angled fsmash (just like our mistakes may cost us a stock from a fresh usmash of yours)... But we have an easier time taking you up to that ~100% mark than what you have taking US to the ~80-90% mark.
I don't think this should be called even.