That dayhike was doomed from the start now that we have more info on their gear/provisions. Yes, the child was probably most vulnerable followed not far behind by the dog, imo.

The dog cause of death being undetermined may be the result of knowing that anatoxin-a can kill animals and Oski was too decomposed to properly rule it out.

It is so tragic to see a group of 4 die this way that, in two months, I never saw one mention (over multiple websites) of that certain award given to those who make this type of mistake and don't make it.