Been in Melbourne more than 50 years and none of those have ever been a problem in normal suburbia! I hardly ever see a cockroach, just your usual ants now and again , same as spiders , one every blue moon in my house , never really see a snake , naturally there will be flies and mosquitoes in summer , hardly ever see a possum , never see toads hardly, they are more in Queensland ,or locusts or cicadas hardly either , unless you go looking for them .