I'm not sure there is any specific info about renting cabanas until your booking window opens. You might be better served looking on the main DIS site, or other sites (Touring Plans, Inside the Magic, etc.) for info.
If you're looking to book one, that would be under "Port Adventures" "Castaway Cay" when your booking window opens. If you are not Concierge, or Platinum, chances are high they are all booked.
They are a super secret LOL! I think if they put more info out on the website about the very few that they have there would be a lot more angry cruisers. Do a search here on DIS for cabanas and you will find lots of info.
Once your booking window opens you will be ble to go to this page.
It will then list the cabanas that are still available. Note: There are just 20 cabanas available on the family beach and 4000 people are the larger ships (Dream and Fantasy) and 2000 plus on the smaller ships (Magic and Wonder). View attachment 126319
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