Do Disney pricing fluctuate throughout the year until sailing?
Yes. As the ship fills up, the price tends to increase. I say "tends" because prices don't increase on every cruise, particularly on cruises that aren't selling well. High-demand cruises (unusual itineraries like Hawaii, Alaska, Europe, and likely, any sailing of the Wish for a while) increase the most.
Some cruises that aren't as full as Disney wants are opened for discounts a few months before the cruise, but there is no way to know in advance if a certain cruise will get a discount. Discount types are Florida resident discounts, military discounts, and general public "GT" restricted guarantee discounts. If you book a GT cruise, you'll have to pay it in full ASAP & it's non-refundable, and they can put you in any stateroom within or higher than the basic category (inside, oceanview or verandah) that you booked. Aside from these specific discount offers, I have never seen prices go down on a
Disney cruise.
You can also try to get a slightly reduced-rate upgrade at the port (from inside to verandah, for example), but
DCL doesn't tend to give big discounts for that, unlike some other lines. It's still going to cost.