Behemoths? deathclaw?

Sorry to break it to you this way, but it ain't happening. Both will be subject to copyright.

could easily just have a monstrous body type for a dragon or other scaly and add in facial customizations with more skeletal or monstrous figure types and additional horn types. You can make your own Faux deathclaw without worrying about copyright infringement.

Its really not that hard to understand that literally putting species like this into the game would be impossible. Get creative and make a custom character that looks like whatever species you want it to be, like what they did with sergals.