If weight is a problem with your PSK, I think that I might lose that Ottorbox. They are great containers, but (in my opionion at least), very heavy for their size.
An old CD/DVD can be better than nothing as a signaling mirror. Nowhere as good as the real thing, but much better than nothing. I would not rely on fire/smoke for signalling, too many reasons why you couldn't get one going when needed.
If you really think that you need some "rescue" rope, there are many ropes in the 7mm size that can function as climbing/emergency ropes. Here
is just one. You are probably metric, so the size (7.7mm) and weight (38 grams per meter) isn't tooooo heavy.
You mentioned plenty of water, but do you drink it straight from the source, or treat it somehow? I don't really know what "quality is good" means, when it comes to actually drinking it. I don't see you boiling much on an esbit stove, and if fires are a no-no, boiling that way is out also. So, does anyone in your group have a filter of some type?
Have a good trip! Pics are always welcome...