A lot depends on what you folks like to do. If you like sunshine and your intent is to get a tan and see some interesting ports, then I would choose the Norwegian Star itinerary. It offers great ports and an excellent price.
However, be prepared to spend more on dining in the alternative restaurants in order to have a fabulous time. If budget is an issue, this might not be the best choice.
If the cruise experience was more important, then I would select the Infinity, as while the itinerary is not a sun oriented one (except the Cabo portion possibly) the ship and dining is GREAT!
Finally, for a balance between the two suggestions above, choose the Vision of the Seas. Great sun time, and also a great cruise experience.
Regarding your question about the weather in San Diego in December....It is a crap shoot. It can be Santa Ana winds, hot and wonderful (as good as it gets) or it can be raining and cold. It just depends and you can't count on it.
Let us know what you decide.