Good ideas.

I don't think the mini glow sticks throw much light, they are good as markers, but I don't think you could count on them for actual illumination.

I'm pretty keen on rescue for my kit, so fishing etc are not priority. I'd focus on fire and signalling:

mirror - you can cut down an existing perspex or glass mirror, sand the sharp corners.

mini whistle

mini-fire steel, or some wproof matches and striker or a Ranger Rick sparker or cut down a sparklite - you may need to trim the lengths to fit ?

Tinder - I'd go for something wproof again, like quiktinder etc or cotton wool with wax (rather than PJ which can be sticky)

Inspired by Eric, you could include a LED (ie just the "bulb" from as electronics shop) and a button battery to improvise a light, you couldn't get much smaller than that.