Every one of these has a scholarly Muslim answer, and pressing them looks like the proof-texting Christians resent when it is done to the Bible. Isn’t this a double standard?

The double-standard worry is fair, and it is why these are offered as questions with the Muslim replies alongside, not as verdicts. The deeper point is consistency. Muslims raise exactly this kind of question about the Bible under the heading of corruption. If the Bible’s difficulties are fair to examine, so are the Qur’an’s, and the honest move is to hold both texts to one standard rather than shielding either.