Yes. But if you new to shaders, I would implement the code without instancing first and verify that everything works. After that, you can still migrate to code to instanced rendering.
BTW: Instanced rendering only reduces the amount of draw calls not the computational overhead in the shaders.
This questions is somewhat confusing. The basic data of you shapes are always defined on CPU side in your JavaScript code. At this place you create your attribute data. The GPGPU examples just shows how you can move as much computations as possible from the CPU to the GPU. This can be useful for stuff like scientific simulations. But you not necessarily need GPUComputationRenderer. The following demo illustrates this: Most of the animation related code of the particle effect is implemented in the vertex shader: