The brochure says the Nautilus has two large quantum fuel tanks, but the stats page says it has one. Which is correct?

The brochure is correct - the stats page will be updated. Also, the brochure doesn't specifically list the missile turret as a separate item, instead it accounts for it in place of one of the listed S3 gun turrets. These differences were due to adjustments that took place after the brochure had gone to print, which was many weeks ahead of the release of the ship and before some of the internal review gates.