I tried exporting & importing your files. But I don’t had no luck either.
I deactivated deform on all bone-layers except the last 3, which seem to be the main deform bones and also reassigned the armature modifier with automatic weights.
The animation looks good in blender but after exporting and importing the vertex groups seem broken. I think that it’s more a blender export problem than a pc issue, as I had never any similar issue with my own (simpler rigs).
Unfortunately I can’t help you with the rigify armature, as I don’t use it.
But maybe you could take a look at some tutorials on how to use rigify rig in unreal engine / unity, as this workflow should work for playcanvas as well.