How did Gecko Moria created marine zombies in Marine War without Hogback around? Back at Marineford War. I noticed something, Gecko Moriah summoned marine zombies from nowhere instantly without Hogback around.These marine zombies have stitches which is only done by Hogback back in Thriller Bark. Some even take the form of animals which is another problem in its existence.

So how did Gecko Moria has done it?
Hogback was useful for Moria, because he could stitch together different parts of separate bodies, thus  only using the strongest parts of those bodies. The best example for this is Sanji's zombie. He is essentially a penguin, but instead of the useless mouth, hogback replaced it with a dogs jaw.

If you look at the marine zombies, none of them has a dog head or bear hands. The closest to this category is the centaur on the left, but that's..."normal". A normal marine doctor should be able, to fix those bodies up.