Radiation...Shouldn't Their Hair Have Been Falling Out?

I don't know, but in films of Hiroshima victims, not everybody is bald. Also it's possible that when the radiation reached the extreme south of Australia, it came upon the inhabitants so quickly and so intensely that it simply killed them before hair-loss could set in...

Yeah, this is something that would take some time -- longer than anyone would have lived due to the more lethal effects that would kill them quickly.

Most completed suicide at the onset of radiation sickness, long before their hair would have fallen out.