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How far do these trips venture from civilization? Are you mostly within walking distance of somebody, or is it many miles out into the wilderness?

It's a good idea to build a kit that stays on your person in case you lose the canoe and/or daypack. First, a couple of long term considerations:
-A life vest more suited to carrying gear
-A personal locator beacon if you venture more than a day's walk or two; if you are injured, a dozen miles may seem like an eternity
-Spare Air tank (this attaches directly to your vest, and can help you in case you find yourself stuck under water

I understand due to the expense, these may take lower priority, but something to think about if you go on these trips often.

I'm not an expert, so the following is just an opinion, so take it for what it's worth. As for your kit, it looks like you have fire down pretty well, but what about shelter and water? Given the nature of your trip, if you ever have to use this stuff, you will likely already be wet which compounds your problem from the start. Some sort of shelter needs to be on your person in case you lose your daypack and canoe; even if this is just a space blanket/trash bag. In addition, unless you strap a water bottle to your person (I don't blame you if you don't, they're bulky-) you'll need to have some way of holding water in case you ever find yourself with only the stuff you have on you. Condoms, gerber breastmilk bags, and so forth take up little room. Then you'll need something to purify it with. Micropur MP-1 tablets or something similar.
Finally, consider
-A handkerchief
-550 cord
-duct tape
-maps in a waterproof plastic baggie
-A waterproof LED flashlight (perferably with strobe option)