You're wrong on the first count primarily because you presume RAG retrieval isn't deterministic. Which it is, even if you format the question differently - as long as the request is coherent and covers the same topic, RAG lookup should be roughly the same, and that should result in the same RAG entries surfaced.

At which point it's the prompt (the hidden/system prompt, not the end user's basic question) that determines just how well that RAG data gets displayed and potentially reworded. But as long as it's essentially used as a human language lookup system + summarisation, its reliability should be generally pretty good, on par with having an on-site paralegal.