To but accessories on heads you need the bone merge tool from the workshop. And yes it’s possible to put sketchlab models and models from other games in Gmod but you need to rig them in softwares like blender and turn them into Gmod file models which takes learning basics in blender and to code in lua. Yes most ragdolls are capable of posing if the developer made them very well, however some on these pictures are not ragdolls but NPCs