If Fetich Death didn't cause Adrian to unlearn Adrian Cosmic Principle she would not be Adorjan. She'd still be Adrian.
Therefore, Fetich Death makes you unlearn charms that say you can't unlearn them.
Also yeah I guess it is specific to GSPs.
Edit: I guess another way of looking at it is that you keep all the transcendence charms - their names and specific-to-a-certain-Yozi text just change.
Because without (foo) Pantheon Unfurling you wouldn't be able to make your new fetich.
But basically you still lose all the specific-to-you parts of those charms. Which would include Gremlin Syndrome, if that's part of Autochthon Cosmic Principle or Autothchon Worldshaper Assumption or whatever.
Edit2: On reading through the Yozi transcendence charms again, they keep making mention of experience points. This makes me wonder what a Primordial's experience point chart looks like.
Obviously, they can't buy Attributes, Abilities or Combos, but what about everything else?
Edit3: I enjoy Ebby's Limit Break. It specifically mentions stealing a child's toy. He is so... petty.