At first, it seems like it'd be best to do some clay bakes rather than final renders but from first glance it seems like they're good concepts but need some work before you go in detailing the busts. The textures seem to be placed as an afterthought - for example the little bit of damage/wear on the chest of the red bust…
I admit that for the detailing part they are pre-mature and some of the details I put in were just there for the sake of it as I use my half baked drawings as reference as well. For the dragon bit I was trying mimic its skeletal structure that of an Ankylosaurus where it its bones (or the outer shell) were literally…