Here's some old artworks I've done. These are low-poly so with more polys we could make a quality work,http://genjix.freehostia.com/#art
How does this sound:
- Me & my sister create a concept artwork for one of your creatures listed.
- You pay $50
- If you want to continue, then we make the mesh to completion with everything over a week.
- You pay $300
Doing all these things you listed is complicated, and it's hard to go back and make changes once you proceed to the next step. Best to get it right the first time- decide on mesh sizes using boxes then on a walkspeed for walk-cycles by measurement. If you later decide to change the mesh then things like UV-unwrapping, skinning, ... will be messed up and need fixing.
It's not something like coding where you place a mesh in-game, tweak it, re-export, tweak, ... It's more like here's the constraints (size, various anim speeds, tri-count, texture sizes, ...), make a model fitting those. Then after each step you don't go back (generally).