I like the head quite a bit, and the rest of the body looks like a good preparation stage. You should make a calm section-by-section study of making them work. Once you're done, which may take a moment, you can actually do some pretty good posing inside of sculptris, using masks and global rotation/scale/grab features.
thx for your answer Taron. You are right, I must focus on separated parts from now. The muscles are exagerated, I need to fix this. About posing, I could use Sculptris, but it's not really confortable for searching different poses.
I think I will have to use Blender (so, retopology)
I tried mixamo online tool for fun, it works like a charm !