the first 2 I'm familiar with, but I don't know about stinging-nettle trees, what are they? I remember singing nettles from being a kid in the UK, and running through fields in shorts, we used to get Doc leaves and rub them on the stings.
I had a close encounter with a baby brown snake last year. I was standing barefoot in my mates kitchen in Byron Bay and looked down to see the snake slither past my toe, about 6 inches away. It was the time of year when brown snakes hatch and they are way more dangerous as the venom is more concentrated. We tried in vain to get it outside, but it got away from us. Neither of us slept very well that night.

By far the worst creature in Oz is the affluent Aussie, they are rude, ignorant, vulgar, have zero taste and shun their convict past with abandon. But we all know from where they came...ha-ha-ha!!!!