The real me inside
One could make it thicker from the beginning but to get a thick result from all angles and all lights it would take a lot which in turn would bog down many computers and slow down renders. Also if the fur is too thick in some angles it will look like plastic.... is there a way to make the hair 'thicker' all over? Babies are so fuzzy! I also 'duplicate layer' for my current hairy gorilla in photoshop, to make the hair look 'thicker'....
Try play with angles and lights to get the best look. Lights pointing towards the fur, from camera angle will give better and thicker fur.
Love your images btw. <3