Since the icon itself has a Mayan flavor and the teaser showed bits of ruins, someone turning into a skeleton, and possible exploration and/or adventure, I'm going to guess that the pack might be called something like, "The Lost Island", or "The Cursed Mountain" or "Danger Island" or perhaps something like "Explorer" or "Ancient Ruins".
I'm wondering if this pack might have been inspired by the "Dangerous" theme that was being voted on back when we thought we were getting an Eco Living stuff pack. It could possibly include some dangerous exploration, a few curses, and new ways for sims to die. But I think it could also possibly contain some archaeology and ancient ruins for build/buy, as well as exotic jungle plants and Aztec designs. Kind of an "Indiana Jones in Mesoamerica" vibe. Maybe there are riddles and puzzles to get into old temple pyramids and jungle mazes. I'd also love to see some exotic animals like jaguars, serpents, and the legendary Quetzacoatl.
But I'm being really hopeful about this. It could, of course, just be a regular vacation isle with a single place to explore and get a skeleton curse.