I have few suggested approach for you, to solve this issue with ease. You need to provide 3 portraits of your desired human face, Front | left | Right.
I will sculpt the face on top o your mesh with Zbrush.
Skin textures will be created using substance painter.
Will Rig it using mixamo so that it can be manipulated universally, using any of your 3d software of choice.
moving on to your questions,
1. Will the avatar you provide be edited later by me?
- Yes, the output will be in FBX or OBJ, so you'll be able to manipulate the rig.
2. Will the avatar you provide can be animated as well, if we want?
- yes very easily, using mixamo, I can teach you, you don't even need any 3D knowledge for animating a human character nowadays.
3. What pose will you submit the avatar in?
- any pose you'd want. once it's rigged, it can be posed quiet easily.
4 . Software you will be using for the task?
-Zbrush for sculpting, substance painter for texturing, blender for pose, mixamo for rigging.
5. What files and file formats will be delivered at the end of the project.
- .OBJ, .FBX, .MA, || also provide you the complete Zbrush project file, substance painter project files too if you want
PS. its a creative task, thus time consuming. Please inbox me for any suggested approach or discussion.
Hope these information will help you.
Thank you.