When I went back to search again this morning, the cheaper one I had found last night seems to be gone. Anyway, our best bet is this one - Celebrity Beyond. It fits within our window of time. I suspect it will be too expensive for some members, however, especially if we want to pitch in for Veranda or Concierge class for my parents. We'll be flying down from Toronto as well, so we have to figure that into the cost, and hooo boy, are Christmas flights ever expensive.
I'm thinking we should consider other Caribbean cruises to open up our options, especially when our timing is so limited.
Thanks for the answers to my other questions! It sounds like I should talk to a TA who's knowledgeable about cruises.
~Kit