Bula, come to Fiji!
I love Fiji and have been there many times over the years and have pretty much been to most of the main touristy areas and stayed in lots of different resorts. Having a chat to me is the best way for me to figure out where I would recommend you stay - there are lots of choices but finding the right resort for you and your family is paramount.
Personally I feel like you get the most authentic Fiji experience by heading out to the Mamanuca or Yasawa Islands and one of my most memorable holidays was on board a Captain Cook 4 night cruise of the Yasawa Islands. Fabulous snorkelling, white sandy beaches, awesome local experiences, yummy food and super friendly staff. This comes highly recommended!!
Vinaka!