Welcome and congrats! I'm getting married next January in Jamaica too! I'm having my wedding at the Iberostar Rose Hall Beach on January 18th. I looked at all the places you are looking at now and I think they all looked nice! Iberostar got the best ratings from what i saw and i like that there are the three options of resorts, the Beach Resort, Suites, and the Grand.
I seriously considered the Grand Palladium but I didn't like how massive the resort is, you have to take golf carts to get around, and that they don't have as nice of beaches.
If you really want to have amazing beaches, water, and sunsets I would check out the Riu Negril. To be quite honest I really wanted to have our wedding in Negril but there will be kids coming and the only resorts in Negril that allow kids are Beaches and Riu Negril. Negril is gorgeous and has better beaches just fewer options in resorts, we're going to Couples Swept Away in Negril for our honeymoon
Good luck deciding! Tripadvisor.com is a great website for resort reviews