Okay, what if it worked like this:
>Oden is out sailing with Roger.
>Orochi invites Kaidou to take over Wano.
>Kozuki Moria rebels and is defeated.
>Moria disappears and they erect a corpse-less grave for him
>Secretly, Moria has escaped and starts to create a pirate crew to defeat Kaidou
>Oden returns and agrees to dance
>Moria returns under the alias of "Gecko Moria" and his Gecko Pirates fight Kaidou
>Oden doesn't recognize Moria
>Moria loses a second time so he decides to go all in on the zombie plan.
Now Oden doesn't look entirely heartless and retarded, maybe?