I wouldnt worry too much about morphing all the layers.
I would use a lot of shake when all the layers come together.
I would hide the other layers behind the final symbol by fading it up on top of them.
I would only morph the final shape. To do this you could use Layer>auto-trace. Then starting with the correct mask it draws for you start keyframing the layer mask backward in time and distorting it.
My Work:
https://www.morecompletefx.com