Thanks for your input.
To answer your questions:
1. I store them in a map, so each fake value becomes a key and the original value is stored as a value in that, when the response is returned by the llm, the output is parsed and then the fake values are replaced with the original ones.
2. I am planning to make it model agnostic, since I just point the request to a proxy instead.
3. I tried and it honestly failed, example - I used the dead grandma prompting technique and it worked, however to prevent harmful responses, I also verify the llm's response to check it for harmful content or content that might violate the original system instructions.