DH and I holidayed at the raddison on denarau a few years ago and thought it was lovely.
We got transferred in a mini van, and it was just us so I don't know if they normally have no car seats or just not because we didn't need one
The rooms were lovely, we had a suite and there was a laundry, a pretty good kitchen, big bedroom and a lounge/dining/sitting area.
We didn't have kids (expecting number one now!) but I remember noticing that there was a kiddy pool area, everything was flat and open and there were lots of kids running around. there were kid friendly activities and restaurants, and they had these wonderful Fijian nannies that would take the kids for either a couple of hours or the day (even little ones) and they were so lovely and gentle with them and were so good entertaining them.
We had a wander around the neighbouring resorts and I THINK it was the Sheraton that the pool areas weren't as child friendly, but they had wonderful restaurants that we took advantage of! Also the Wyndham one had lovely bog open grounds that had lots of kiddies running around.