Good luck with that. You know it is cyclone season until the end of april and probably later this year because of an extra strong La Nina? A boat would have to check in at Papeete first then it is about 870 miles say a week sailing. I doubt there would be many offering.
There is a freighter running, the Tuhaa Pae but the frequency is uncertain 2 weeks -2 months. Fare is E67 deck
or 392 in comfort each way.
There is a reef check programme although it is unclear how much it covers at this stage which might be worth checking out.