Hi
Naigani is off the beaten track and can be quiet. Great for families 3* style but loads of room inside and out. Small but OK pool.
Some great dive spots especially if they take you to E6 or Wakaya - both a bit of a trip. I have stayed there several times and it is very popular with local ex-pats for weekends getaways.
Malolo Lailai - island is nice but quiet busy with a few resorts there as well as the yacht haven. Diving is not a patch on Kadavu or Naigani but still OK, if you aren't too bothered.
Fiji Palms - I presume you mean Fiji Palm Beach Club at Pacific Harbour. Well strange to say, I don't know it at all but I must have driven past it hundreds of times I guess. Trip advisor reviews sound about right though. Old but being slowly renovated. One thing to note is that Pacific Harbour is on the wet side of Fiji so much greater chance of rain, but the diving on offer via Aquatrek or Beqa Adventure Divers is first rate, including the Shark feeding dives.
I hope that helps.
Greg