Just off the top of my head for a few of your questions. Each person has their own individual backpack with their own gear in it, so they are independent if separated. And each pack is decent quality. Mrs. Hikermor has her own bag with good contents...

'be able to reflect light for nighttime safety and still be able to blend in" I don't get your meaning here. I am not in the least concerned with blending in. Finding splinting material is trivial and easily done, although I would prefer to use a SAM splint. If you are referring to the whistle attachment on the chest strap, these are commonly available accessories - I have several.

I think we are coming at this from different perspectives. You seem to be envisioning the somewhat mythical total societal collapse where everyone goes crazy and total chaos ensues.

I am more concerned with getting out of the woods and back to society, although societal upheaval is a possibility. Thus I am more concerned with high visibility. This is far more common circumstance.

This brings to mind that the kit omits a crucial item - a signal mirror - don't leave home without it.

More later - this is a fun project. Thank you, Phaedrus, for stirring up the ashes....