Honestly, if Islands is a thing, I'm pretty sure it's gonna be a standard pack, and if that's the case, I'd go with something like:
Notice how I subtly made it into Oceania themed, kinda like how the Twilight was subtly North America
- North Island brown kiwi
- Tasmanian devil
- Fossa
- Tree kangaroo (any species)
- Large flying fox (WE)
I really don’t think a Tree Kangaroo will be part of an Islands pack. I can see a Rainforests pack happening before, and it being a part of this one.
I just don’t see an Islands pack having such a huge Oceania focus, when there are islands all over the world that still need representation. The Caribbean, Greenland, British Isles, Mediterannean, Hawaii to name just a few. By limiting an Islands pack to Oceania, you might as well just call it Oceania Pack (+ Fossa).
This is why I think we’ll get a Rainforests pack first, with the Tree Kangaroo. Followed by Islands with Tassie, Kiwi, Fossa and Cuban Croc.