What kind of fixed blade do you have there??

What about signaling? Signal mirror. Include a whistle at the very least.

I'd lean toward a headlamp rather than a hand held light, but that's just me lately. I'm a BIG fan of Princeton Tec EOS headlamps - I have them all over my house.

Personally Il don't care for cheap plastic ponchos. They are typically so flimsy. I'd rather stow large (30-50 gallon) bright (orange) plastic bags that can act as a ground cover and a rain/dew protector. Buy a box of them and share them with others. They make great gifts!! :-P

The backpack filled with leaves can act as a insulating seat.

I'd also include a map of the area, a compass, a GPS, extra batteries for the GPS, and a PLB.

I might recommend cutting cord into 16-20 foot lengths and bundling them. I cut a 100 foot hank of cord into six 16 foot lengths. That makes it easier to manage (less tangling) and MUCH more likely to be used on a regular basis - for all sorts of things. Maybe keep one 50 foot or longer length of poly line (stretches less than nylon).