I tried to do this procedure with the file as you shared it. My patience and the CPU power here didn’t match. So, I stopped it.
I wanted to find something that works faster, at least for the file import and export.
First, I deleted the 10K+ nulls in the file, a leftover from the Voronoi Fracture, I assume. They are useless in the file. But might take up a lot of time.
Secondly, I tested the three main parts, the egg, the little dynamic island, and the primary environment. Only the Main (big) part caused trouble. I selected all none moving parts and placed them on a layer. I did so with a lasso first, roughly, then more object by object, which meant, the Big animated part had only a few hundred objects that needed to be converted. Those were the ones with the little green filmstrip, handpicked in a few hours (I needed to go one time through to see that it works. I would not look forward to doing it again, there must be a better way in the future, I will submit a suggestion). Anything else from the group, I merged. There is one single chunk from the many thousands of static objects, that failed. I guess that is a little bit of modeling, but this was not of my interest in the workflow.
With only 408 objects to process for animation, I was able to have this processed in hours, instead of a day or so. Then I wrote the Animation Clip back as PLA.
The complete export to FBX was then done under a minute. The folder with the PLA/FBX is quite large. You will find a link in your private Messages here on Cineversity.
Alternative to this, the Correction deformer can help with some other objects to “harvest” the point information, but I think it is better to find a way to use the clones axis, for objects that don’t really animate the vertices…
My best wishes