I'm taking the same flight route, bar that I actually return to Melbourne from Osaka via gold coast as well. I hope the Jetstar flight is worth the $300 saved from not going with a major carrier.
My advice with hotels is to thoroughly shop around. I found that every day I searched I found a better deal than with the previous day.
Admittedly I haven't done nearly as much research on nightspots than I have on toygawking. Any more suggestions on cool places to hang out Lord Zed?