Ha. Wildlife. it's a blast. Several of Sydney's beaches have been closed this weekend because of a mass influx of 1000s of bluebottles, nasty little stinger things (not the flies) that are carpeting the beaches.
Cane toads are mostly in Queensland so not relevant to you?
Snakes are not that common in built up areas, but you learn not to walk in thick leaf piles.
Spiders - ah. Well, the first thing you need to do is familiarise yourself with the native spiders of Australia - the 3 main ones to avoid are the redback, the white tail and the funnelweb.
Redbacks are very obvious and should be stamped on at every available opportunity (with shoes ON of course!) - any outdoor toys, equipment etc. should be regularly checked for them and their messy "web" and flushed out with hoses. (and stamp on them as well). Don't leave closed shoes outdoors (like trainers, wellies etc.) as they like to get into the toes.
White tails - if you find any indoors, get the house fumigated - they don't make webs as such, they like to hide in things like piles of clothes, bedding etc.
Funnelwebs - you don't see these very often, which is good because they are the nastiest. However, the black house spider, which tends to make nice lacy webs in window corners, also makes little funnels in these webs and causes even native Aussies some distress (yes, I'm talking about you, DH!) and unnecessarily violent action.
Huntsman spiders are big and scary but not that dangerous unless you tread on one - the bite is painful and can get infected but isn't that venomous.
A good tip I was given by a native Aussie (but not DH) - spiders that make normal hanging webs (like in the garden) are not the dangerous ones.
Cockroaches - bane of my existence - never leave food out anywhere, seal it all in tins/ tupperware in your drawers etc. They grow up to the size of small mice (killed one that big in the shower today). Fumigating the house will stop them for a while.
Jellyfish are seasonal and there will usually be signs on the beaches to tell you when they are out and about and to prevent you from swimming.
If you go wandering in grassy bush, watch out for ticks - DS got one in his little forearm, it was possibly one of the most disgusting sights, seeing this creature half buried in his arm and having to hoik it out intact.
Prevention is better than cure - teach your children not to play with wildlife, just in case, especially the littlest ones.