Your list is fabulous! A few suggestions to add to it.
If you find yourself low on cash, instead of using the ships ATM (the price is high enough that you should get to keep it) go to the casino and get cash. Tell them it's for the slot machines, not the tables. I've never been charged extra for the 'advance'.
If your luggage won't fit under the bed, as some of ours won't, storing it on the balcony is an option. You may want to bring it back into the room during the day, especially if you're in port and the deck is going to be washed. Bring a couple of large garbage bags to slip over the luggage with while it's outside; eliminates the salt deposits.
Don't just get a cheap power strip, get a good one with a surge suppressor function for the valuable electronics.
While you shouldn't bring unauthorized alcohol on board, if you do choose to bring it put it in empty water bottles, etc. Even clean shampoo bottles, and so on. No problems getting it on board.
I like coffee. Lots of it, in the cabin. I bring the prepackaged coffee and filters you can buy at stores. Maxwell House? Saves begging the room steward for more.
Extra hangers. Some ships seem to have very few, and it's easier to have a few than try to hunt them down.
Snacks for the kids. Such as Hershey Bars, Reese's, whatever everyone likes. Much better than paying a dollar a bar in the ships store. Healthy snacks too if you're so inclined. Sunflower seeds, nuts...