The rocks are 4 fake stone shaders merged, but this time I added a compute normal with a very small patch size (0.05 or so) under the mix and had the followed by a surface shader with a slight offset in displacement. That blew them up a little. Then added some tiny displacement (and partial color addition and a bit of reflection) overall through a transform (to world) shader into the child input.
But they do overlap here and there, just hitting seeds a few times until it's good enough.