Topology is how the model is shaped. The edgeloopflow is a very impoprtant thing.

Reducing polycount means to cut away edges. Cut away the wrong edges and your mesh doesn't look like your model anymore. And you are also in trouble with animation when the edge isn't longer there where it should bend. You may get it to work in the end. But is more work than shaping it from scratch.

Best advice in this case is to use the Makehuman mesh as a reference. Then model your own low poly mesh around. Makes really no sense to even try to reduce the poly count of the Makehuman mesh.