Oz isn't as strong as everyone thinks. Here's how to easily beat him. Get Sanji to get a big piece of meat, and hid a bag of salt in it. Just like Luffy, the guy would eat it whole. Keep luffy away cause he would eat it. Thats how to beat Oz. They can all be tricked somehow. Zoro's zombie, just promise him a new sword if he eats the salt. Sanji's zombie, make Nami say she'll kiss him if he eats the salt.
Making Moria say those words...well you would have to get him down for the count. I imagine that Luffy will use the light to make the shadow disappear...or the darkness or whatever, and then Moria will surrender.