Help with Batches

Hi everyone, i'm having trouble to optmize my batches and SetPass calls, all my enemies are using bones with Anima2D so i need to use 4 skinned mesh renderers in each goblin for example, i'm currently using texture atlas, also my static and dynamic batch are not working perfectly, is there ANY way at all to minimize this calls? i'm developing for mobile and there's only 20 instances of enemies in the scene.