We (spouse, 9-year old daughter and 7 year-old son) flew in on Jet Blue on the day of the cruise. It was a 7:40 am flight that landed at FLL at 10:30. Got all luggage and cab by 11:00 am and at line for embarkation by 11:20. embarkation took a bit over an hour, which is about standard. Carnival asked that I print Fun Pass, which was never used. We also had to fill out Bahamian entry papers.
When we checked in, we found that although we requested 6:15 pm dinner, we received 5:45 pm. Wasn't happy about that and was told to speak to maitre d. Maitre d was of no help and explained large group had totally booked the 6:15. In any case, he told us that it's normal to enter at 6 pm for the 5:45. That had to do.
I'm only reviewing things we used extensively.