Been there a few years ago.

There is a french guy in Port Vila that trying to promote kiting, and has a school that teaches at Hidaway Is. He was on Seabreeze about 2 years ago you might be able to search all the info.
Wind can be fickle and gusty at Hideaway.

I wouldn't trouble myself with Kakula, as you have to pay to kite there.
can't remember how much but it might have been $50, for each kiter.
Instead Go to the Beachcomers Resort just south of Kakula Is. on the NE corner of Vanuatu.
There is a big lawn area to set up on just south of the resort.
There is also a few houses that you can rent. Cheap
Kite inside the reef for good flatwater
There is a rock that covers and uncovers out in front of the village to the south of
Beachcomers.
On the right tide you will get good kickers etc.going out over the reef

If you look at it on Google Earth you will see white water to the east. Maybe 800 meters offshore.
We never kited out there, but it looks worth exploring if you want waves.
Talk to the guy behind the counter at beachcomers and they will hire you a rescue boat if you want to do a down winder.

If you buy a burger at Beachcomers you can float around in the hot spa pool for nothing.
Really great after you've been kiting for a few hours.

If the wind gets around to the north enough you might get great flat water from the village on the corner, north of Beachcomers and South of Kakula.
sandy bottom and loads of area.

Not sure if the road around the island is now all sealed but that will make a big difference.
Hope that helps...

dude if you go to vanuatu you cannot go past espiritu Santo. go dive the wrecks and reefs. hire a canoe and go to the blue hole. oh yeah, and take the missus, or just find a new one. she'll love it