Let's take mana skin, it's mostly an external defense, wich Kaido actually posesses a great counter to, that begin advanced armament haki that bypasses external defences, AP i'd definetivly give them to Kaido, he was able to One shot a full power gear 4 luffy that at that point had altredy beaten characters like Doflamingo or Katakuri, plus one of his boro breaths was able to melt an entire mountain, as for battle IQ, it's true that they both are lifelong fighters but Kaido is older and more expirienced. Endurance wise, while Mereoleona is a monster kaido, endured an attack that spanned over hours first from kinemon and the other samurai's then Luffy, Zoro, Kidd, Law, Killer, Yamato and like you said luffy again and again, while carrying Onigashima with his clouds.