You can use 150K per person to fly Delta to Australia on Korean Air (via Seoul) or on Virgin Australia (via LAX). The problem is getting to the gateway domestically, since Delta rarely releases low level award space on many domestic routes. It will take some hair-pulling with the award calendar. Korean Air also has blackout dates for their awards.

You can also transfer Chase points to United, which will let you redeem on Star Alliance to Australia. While a direct flight may be tough to find on United/Air New Zealand. It will be tough since you'll have to double-connect between ATL and LAX/SFO to get to the international gateway anyway. However, you can route via Asia on partners like Asiana, ANA, and Thai. UA charges 135K pp roundtrip between the US and Australia, so you'll need about 65K UR more.