Major Project - Model Template

I have worked out the major forms, though still not happy with the boots and bottom of trousers, so this is subject to change. But knowing how the head and helmet work together, I can get working on rigging the actual head.

Though this is a zbrush model, the topology is not high, I want to use this to test certain pivot points on the rig I intead to use. then can I start retopologising and texturing the model.