I'm adjusting the clothing, skin materials, and fit (I gave him a little belt and shoes). I will pose him next and then follow up with a face pass. I need to figure out movie settings on the renders as I get odd aliasing in them...

I shifted everything to Unreal Engine and started making a custom skin shader for him; the clothing is still a block in with a custom shader. You can follow along in realtime on this project on my Twitter or X

I threw this sculpt into marmoset to see if there was still any life in him.