Hello. I have moderate experience with using Blender for Amnesia, and I can tell you this:
-First, make sure you follow this tutorial closely:
https://wiki.frictionalgames.com/hpl2/th...[]=blender
-In Blender, importing a .dae and exporting it as .dae causes model corruption.
I've had the best results when importing an .fbx and exporting as .dae, so try using this format.
This applies both to models and animations.
-You should be able to copy the rig from Amnesia and use the original monster animations (import an Amnesia monster, delete the mesh, import your monster, allign your monster with the rig.)
-I'm not passing any judgement, but keep in mind that ripping assets from other games is frowned upon. Make sure to at least credit the creator if you're gonna use them.
Hope it goes well!