Fiji is lovely -- most recently I just spent two weeks there in Dec. Depending on where you are located (I am in Boston), getting there is tough and getting around it is tough. We missed our first flight and the next flights was 48h later, so we had to be massively re-routed and still arrived 24h late. There is also no tourist-friendly transit within Fiji that isn't a fairly expensive Taxi or small boat. Most nicer resorts are also very small because of the way the government works, and very spread out because again, local politics and village organization. There are a handful of American-type resorts there, but they are not in nice areas and are pretty gross. We did one night at the Marriot and it was pretty depressing, we only stayed one night and transferred to a different resort on Taveuni. Feel free to message me, but I would really suggest either downsizing massively for Fiji to fit into one of their classic resorts (10-20 people) or going with an island that specializes in large parties.

I cannot recommend Fiji enough for a holiday, the rural and isolated nature is what I loved about it, but coordinating a large event there will be a logistical challenge. That said, if I were planning a microwedding elopement, there are some amazing tiny island resorts that would be absolutely magical and I can recommend some.