Might I suggest the ability to boil water.
I notice that you have fish hooks, but those are more of a long term survival item. If you dunk and come ashore, your immediate need is to warm up. The ability to get some form of hot liquid (be that tea, coffee, soup, even just plain hot water) into your system could make all the difference. (I know that the requirements to become a canoe trip leader according to the British Canoe Union are that you have to be able to get a fire going and a hot liquid into your system within ten minutes.)

I always include an aluminum baking tin (one of the small loaf tins. Unroll the rim, fold it to fit in a tin, bash it with a dead blow mallet, and put it in. I folded and unfolded three to see if the folding and bashing caused any holes to form. I didn't see any. (And in an emergency, duct tape will fix that.) I will try one again in a year to see how it stands up. I just find it much easier to unfold and put over a fire than trying to fold a piece of tin foil into a vessel.

Another thing to consider is some form of clothing to change into. Maybe some poly pro long johns, perhaps some socks and a balaclava and gloves also. Vacuum seal it into as small a package as possible. Carry it in the cargo pockets of your pants. While not much, some barrier against the cold and wind will certainly help. And also start wringing out your clothes as soon as practical to get as much water out as you can.

HTH

Thomas