Heya, hmmm... Def should not be doing this, but I'm unsure why. For me putting the prefabs in a similar order in the hierarchy doesn't cause the animations to break entirely. Try putting the AnimPack prefabs at the end of the hierarchy of the avatar instead of the beginning and see if that fixes things.
I'd recommend joining the Discord as it has help channels for easier troubleshooting. I am def thinking of making a quick start video, just haven't found the time to do it yet.