Layout group

some time ago I started working in a layout group optimization, but sadly I'm stuck in how to advance... my goals were:

1. Create from the very beginning so many elements that the layout groups needs, and call the force rebuild only when needed... not when every element is added (for this I was thinking to create my own layout group based on the horizontal or vertical layout group and call the force rebuild only when I had finished to create child elements)
2. Work some way that enables animating elements dynamically, like the typical scale of the childs (with delayed time between them) but then I was thinking in animating position from a origina (for example from a chest to their final position in the layout) too but then it was impossible because the layout code is preventing me to move the child elements...

Any ideas, thoughts in how to achieve all of this?

Thanks!