I don't live in the area at the moment but I've purchased very close by and have researched the area somewhat.
I am lead to believe that the smell problem from leaking sewerage into the creek has been fixed and there isn't any bad smell anymore.
As for mosquitoes and other biting insects, I can't tell you but I look forward to you telling me as you will be moving into the area before me.
I heard it has alot at certain times of the year due to close proximity to nature and water.
Crime, apparently it's common but residents say it's no more than anywhere else on the Gold Coast but it's important to invest in a good security surveillance system.
The QLD police have an online crime map that you can look at for a general guide. Below is the Url.
As for flooding, the Gold Coast council has an interactive map and you can check out the flooding Level. I've posted the url below.