I have sailed twice out of Miami on RCCL and I can only help with a couple of your questions. I do suggest checking out the Miami board on Cruise Critic as there are a lot of helpful suggesstions there.
1. Which hotel (s) do you all recommend, we will need one night for 4 people.
For hotel, it really is subjective as there are SOOOO many to choose from. Much, much more than Port Canaveral. Also, it depends on what kind of experience you want. Do you want to stay on the beach, close to the port, just someplace inexpensive to rest your head, or close to the airport.
On one cruise we went the night before and I believe we stayed at a Ritz Carlton. It was nice, connected to a convention center but it was on the train line and we took it down to a shopping center to walk around and get dinner the night before the cruise.
3. Which airport when we get back from the cruise? Some on here have said Miami, others FLL.
Since I live near Orlando, we have driven to both cruises, but I do feel qualified to answer this question
. I say which ever airport is cheaper. It really doesn't matter. Yes, FLL is not as close, but not so far for it to make a big enough difference. If your flights are both the same price, then go for Miami.
Enjoy sailing out of Miami. In my opinion, if you love to cruise, like we do, you should sail out of Miami at least once. It is absolutely gorgeous. Make sure you are out on deck or on a verandah so that you can see everything as you sail past.