To bake pivots and specifically to bake motion, I think you need to look at the Houdini GameDevelopmentToolset
https://github.com/sideeffects/GameDevelopmentToolset [
github.com] and the stuff that Luiz Kruel did to bake and convert Houdini simulations to shader and texture driven animations in Unreal.
Aside from that you should look at the tools that already exist in Unreal. In particular, look at GPU particles. Also Unreal does have a premade shader function that you can plug into the world offset so that quads always face the camera.
