It looks like you can get away with a two part silicone mold on those guys. Seal your sculpture with a few light layers of crystal clear and matte finish. You can do a very light release too if you want. throw down a small piece of clay wrapped in cling wrap (or some foam if you have it. Anything soft really) to lay the sculpture down without damaging. Then clay up your diving line, taking out any undercuts. Throw in some round keys and a foam core wall and pour up your first half. Wait for that to set, flip the sculpture, wall it up again. Release your silicone with ivory soap + alcohol mix to release it. Let it dry and do a few layers of this. You can also do a very light misting of 301 spray. Then pour up the second side.
You could also possibly build a box around it while it is standing up and pour up a one piece box mold. You would need to strategically cut it and it might be a pain to take out, but you will get really good seam lines.
Also don't forget to add in bleeders in say those toes and some similar areas.