Blender Blendshape meshes, UVs, and textures Here is what I want to achieve

Input: Three face models that are correctly UV mapped different textures.

Goal: Create a blendshape and animate between them.

Say A is a face with mouth and eyes closed, B is a face with eyes open, and C is a face with mouth open.

Then for, A(0%), B(50%), C(50%), I want eyes and mouth half open, and this can be achieved by simply using shape key. Morphing 3 textures are also possible by changing the balance of diffuse of 3 materials.

But the problem here is that it uses the UV coordinates of A, not blending of B and C, so now the morphed texture doesn't make sense.

Is there any way to solve this? eg. something like shape key for UVs?
You already have the MESH part covered in your setup (standard) shapes. Good.

Now you also need to setup drivers to the SHADER aspect of this.

And it´s due with a simple FACTOR setup (greater than) Evaluation. If it returns a number above ZERO, expression is true, it SHOWS the texture. If it´s false, return TRANSPARENT (or default texture).
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https://www.youtube.com/watch?v=0glf-acMvcw