Best way to do it is to use families.
+For Each (Ordered) FAMILY, Sort by Y Ascending
-> FAMILY : Move to top of layer
If you can't use families, then the Z-sorter plugin mentioned earlier would work fine, too.
Don't really recommend any other methods since the above two are the simplest ways to do it.
Moving characters from Layer to Layer is not the same as changing the Z order. In each layer you have an X,Y, and Z coordinate. Z decides which object gets drawn on the top. Moving from Layer to Layer isn't practical for top down games because if you have a large number of characters/objects on screen, you'd need a layer for every one of them in order to properly display "depth", in every layout. Way more work than necessary, and likely a bad idea for performance as well (haven't tested layer limits myself). Layers are better used for parallaxing, HUDs, forest canopies, cloud shadows, weather, fog, environmental effects, backgrounds, collision layers, etc... rather than sprite sorting.
Besides, why make 100+ layers to accomplish what can be done in 1 event?