Generally in discovery a party is permitted to request anything ["reasonably calcu^H^H^H^H^H^H^H] "any nonprivileged matter that is relevant to any party’s claim or defense and proportional to the needs of the case."
So aything relevant to CA's claims against Amazon, or Amazon's defenses, is fair game. If your client is being sued for a Zillion dollars, and you don't dig up every possible way to discredit the plaintiff's key witnesses, you're not doing your job. This means asking about every possible connection between the plaintiff and the witness, their possible biases and gaps in credibility.
So aything relevant to CA's claims against Amazon, or Amazon's defenses, is fair game. If your client is being sued for a Zillion dollars, and you don't dig up every possible way to discredit the plaintiff's key witnesses, you're not doing your job. This means asking about every possible connection between the plaintiff and the witness, their possible biases and gaps in credibility.