A footnote to your excellent list: there’s a considerable amount of walking on uneven surfaces. Nothing like what we encountered on our (non-Viking) trip to the Holy Land, but we had a couple people who couldn’t do it. They spent some time in a garden area instead, as I recall.
Our guides were terrific (we had a separate guide for the long bus trip, and she was interesting), and I highly recommend the excursion. But oh, the crowds.
Finally, I recommend Washington Irving’s “Tales of the Alhambra” for a glimpse into what it was like a couple hundred years ago.
On my bucket list: to stay overnight at the hotel inside the Alhambra and see the place when the mobs are gone.