I have had good responses using the Platinum Line, I have found them helpful and creative especially when you are wanting to use points. Regarding the Caymans, there is limited hotel accommodation on this Island thus rooms come in at a premium, plus April would still be considered high season. That being said by booking this far ahead there is no way the hotel is booked up, unless they have blacked out for points redemption to which I would say is patently unfair.
This is something you could discuss with the Plat Res person.
Hi sjames99, and welcome to Marriott Rewards insiders! I'm very excited to have you join our community. This forum, as you've likely already learned, is a great place to share travel stories, insights and ideas, and post questions such as the one you've posted here. The other Insiders, as jamesdean has already demonstrated, are very well versed travelers and Rewards members, and are always happy to step in and help. You can also reach out to myself, carat or deannad with any questions you have. We make up the moderators for this forum and are always happy to help as well.
Thanks for posting, and congrats on your engagement!