Need help sorting out a sensible travel route for Vanuatu (via Brisbane)

Hey guys, I've recently started roughing out some plans for a big volcano based solo tour of the Pacific next year, and after finding out about Vanuatu's amazing volcanoes I'm determined to fit it into my itinerary.

Unfortunately I'm having trouble figuring out how to get there, visit both Tanna and Ambrym islands and move onto my next destination (Hawaii) without travelling in circles multiple times and spending a fortune on flights. The route I have right now consists of 7 flights. Brisbane to Port Vila, Port Vila to Tanna, Tanna to Port Vila, Port Vila to Ambrym, Ambrym to Port Vila, Port Vila to Brisbane, and finally Brisbane to Honolulu. It's a little ridiculous I know!

As Vanuatu is home to some of the most accessible active volcanoes in the world I'm not really willing to scrap it from my itinerary (nor Hawaii, as I am visiting a friend there and again the volcano park is very accessible), so if there's no simple way to do this I'll just have to deal with it, but if there is an easier way I'd really love to hear it!

EDIT:
Looks like I have managed to cut it down to 6 flights by going straight from Brisbane to Tanna (according to the Air Vanuatu site this is possible), and flying to Hawaii via Air Pacific with a stopover in Fiji will cut down costs (although their site is being weird at the moment so I'm not totally sure if that will work).

Looks like I have managed to cut it down to 6 flights by going straight from Brisbane to Tanna (according to the Air Vanuatu site this is possible),

There aren't straight flights from Brisbane to Tanna according to the current schedule (valid till Oct. 27th) available in the web of Air Vanuatu (If I'm reading it properly). I couldn't find the international schedule valid since Oct. 28th.

and flying to Hawaii via Air Pacific with a stopover in Fiji will cut down costs (although their site is being weird at the moment so I'm not totally sure if that will work).

It'll depend on your travel dates but you should be able to fly from Port Vila to Honolulu changing planes in Nadi at least once a week. This could be a better alternative than backtrack to Australia. BTW, if you consider the option of backtracking to Australia, you could make it to Sydney (instead of Brisbane) and fly with Jetstar from Sydney to Honolulu.

There isn't a better way to make your route. There aren't direct flights from Tanna to Ambrym (neither with the current Schedule nor with the schedule valid since Oct. 28) and there aren't direct flights from Vanuatu to Hawaii. If there's a direct flight from Brisbane to Tanna on your travel dates, that would be the only way to save a flight leg.

Another alternative route between Vanuatu and Hawaii would be via New Zealand. If you haven't been yet, a stopover there could net you additional very impressive volcanoes.